American Sign Language
American Sign Language (ASL; less commonly Ameslan) is the dominant sign language of the Deaf community in the United States, in the English-speaking parts of Canada, and in parts of Mexico. Although the United Kingdom and the United States share English as a spoken and written language, British Sign Language (BSL) is quite different from ASL, and the two sign languages are not mutually intelligible.
ASL is also used (sometimes alongside indigenous sign languages) in the Philippines, Singapore, Hong Kong, Dominican Republic, El Salvador , Haiti, Puerto Rico, Cote d'Ivoire, Burkina Faso, Ghana, Togo, Benin, Nigeria, Chad, Gabon, Democratic Republic of the Congo, Central African Republic, Mauritania, Kenya, Madagascar, and Zimbabwe. Like other sign languages, its grammar and syntax are distinct from any spoken language in its area of influence. While there has been no reliable survey of the number of people who use ASL as their primary language, estimates range from 500,000 to 2 million in the U.S. alone .

# History of ASL
In the United States, as in most of the world, hearing families with deaf children often employ ad-hoc home sign for simple communications. Today though, ASL classes are offered in many secondary and postsecondary schools. ASL is a language distinct from spoken Englishreplete with its own syntax and grammar and supporting its own culture. The origin of modern ASL is ultimately tied to the confluence of many events and circumstances, including historical attempts at deaf education; the unique situation present on a small island in Massachusetts; the attempts of a father to enlist a local minister to help educate his deaf daughter; and in no small part the ingenuity and genius of people (in this case deaf people) for language itself.
Standardized sign languages have been used in Italy since the 17th century and in France since the 18th century for the instruction of the deaf. Old French Sign Language (OFSL) was developed and used in Paris by the Abbe de l'Epee in his school for the deaf. These languages were always modeled after the natural sign languages already in use by the deaf cultures in their area of origin, often with additions to show aspects of the grammar of the local spoken languages.
Indigenous Peoples of the American Plains used Plains Indian Sign Language as an interlanguage for communication between people/tribes not sharing a common spoken language; its influence on ASL, if any, is unknown.
Off the coast of Massachusetts, on the island of Martha's Vineyard in the 18th century, the population had a much higher rate of deafness than the general population of the continental United States because of the founder effect and the island's isolation. Martha's Vineyard Sign Language was well known by almost all islanders since so many families had deaf members. It afforded almost everyone the opportunity to have frequent contact with ASL while at an age most conducive to effortlessly learning a language.
Congregationalist minister and deaf educator Thomas Hopkins Gallaudet is credited with popularizing the signing technique in North America. At the behest of a father who was interested in educating his deaf daughter, Alice Cogswell, he was enlisted to investigate methods of teaching the deaf. In the early 1800s he visited the Abbe de l'Epee's school in Paris and convinced one of the teachers, Laurent Clerc, to return with him to America. In 1817 they founded the American Asylum for the Deaf and Dumb (now the American School for the Deaf), in Hartford, Connecticut, to teach sign language to American deaf students.
It was at this school that all these influences would intermingle, interact and what would become ASL was born. Many of the school's students were from Martha's Vineyard, and they mixed their "native" sign language with Clerc's OFSL. Other students probably brought their own highly localized sign language or "home sign" systems to the mix. Undoubtedly, spontaneous lexicon developed at the school as well. If there was any influence from sign language of indigenous people, it may have been here that it was absorbed into the language.
Interestingly, because of the early influence of the sign language of France upon the school, the vocabularies of ASL and modern  French Sign Language are approximately 60% shared, whereas ASL and British Sign Language, for example, are almost completely dissimilar.
From its synthesis at this first public school for the deaf in North America, the language went on to grow. Many of the graduates of this school went on to found schools of their own in many other states, thus spreading the methods of Gallaudet and Clerc and serving to expand and standardize the language; as with most languages though, there are regional variations.
After being strongly established in this country there was a bitter fight between those who supported oralism over manualism in the late 1800s. Many notable individuals of high standing contributed to this row, such as Alexander Graham Bell. The oralists won many battles and for a long time the use of sign was suppressed, socially and pedagogically. Many considered sign to not even be a language at all. This situation was changed by William Stokoe, a professor of English hired at Gallaudet University in 1955. He immediately became fascinated by ASL and began serious study of it. Eventually, through publication in linguistics journals of articles containing detailed linguistic analysis of ASL, he was able to convince the scientific mainstream that ASL was indeed a natural language on a par with any other.
The language continues to grow and change like any living language. In particular, ASL constantly adds new signs in an attempt to keep up with constantly changing technology.

# Linguistics
ASL is a natural language as proved to the satisfaction of the linguistic community by William Stokoe, and contains phonology, morphology, semantics, syntax and pragmatics just like spoken languages. It is a manual language or visual language, meaning that the information is expressed not with combinations of sounds but with combinations of handshapes, palm orientations, movements of the hands, arms and body, location in relation to the body, and facial expressions. While spoken languages are produced by the vocal cords only, and can thus be easily written in linear patterns, ASL uses the hands, head and body, with constantly changing movements and orientations. Like other natural sign languages, it is "three dimensional" in this sense. ASL is used natively and predominantly by the Deaf and hard-of-hearing of the United States and Canada.

## Iconicity
Although it often seems as though the signs are meaningful of themselves, in fact they can be as arbitrary as words in spoken language. For example, a child may often make the mistake of using the word "you" to refer to themselves, since others use that word to refer to him or her. Children who acquire the sign YOU (pointing at one's interlocutor) make similar mistakes  they will point at others to mean themselves, indicating that even something as seemingly explicit as pointing is an arbitrary sign in ASL, like words in a spoken language.
However, Edward Klima and Ursula Bellugi have modified the common theory that signs can be self-explanatory by grouping signs into three categories:
- Transparent: Non-signers can usually correctly guess the meaning
- Translucent: Meaning makes sense to non-signers once it is explained
- Opaque: Meaning cannot be guessed by non-signers
Klima and Bellugi used American Sign Language in formulating that classification. The theory that signs are self-explanatory can be conclusively disproved by the fact that non-signers cannot understand fluent, continuous sign language. The majority of signs are opaque.
Generally, signs that are "Transparent" are signs of objects or words that became popular after the basics of ASL were established. There are, of course, exceptions to this.

## Grammar
Stokoe started a phonological analysis and devised a phonemic alphabet rather like the International Phonetic Alphabet. Other linguists have since extended sign language research to the morphology and syntax of ASL as well as other sign languages.

### Phonology
Stokoe called the building blocks of signs 'cheremes', from the Greek cheir- 'hand' by analogy with the word phoneme. However, it has since been recognized that they are cognitively equivalent to the phonemes of oral languages, and since Stokoe's time the terms 'phoneme' and 'phonology' have been used for all languages, oral and sign.
These linguists have divided ASL signs into several elements or features: hand shape, palm orientation, hand movement, hand location, and non-manual features such as facial expression. In early theoretical approaches, movement was treated as simultaneous and/or sequential motions of the hand, on par with other features; while in many more recent approaches, movement is treated as the tempo of the language rather than as a feature per se: Signs are divided into segments of movement and hold, each of which consists of a set of the other features of hand shape, orientation, location, plus any non-manual features.
In addition to linear movement in the six fundamental palm directions of up, down, in (toward the signer), out (away from the signer), center, facing opposite your dominant hand is (contralateral), and the same side as your dominant hand (ipsilateral), of which diagonal movement is considered to be comprised, phonologically distinctive sign movements include twisting of the wrist, bending of the wrist or fingers, touching a location, crossing hands or fingers, grasping, entering (inserting the hand or fingers between the fingers of the other hand), opening the hand, closing the hand, approaching a location (or the hands to each other), separating from a location (or the hands from each other), brushing a location, wriggling the fingers, exchanging hands, and circling motion of the hand or arm. These may involve 'salient' forearms, so that crossing the hands is realized as crossing extended arms. Palm orientations are, by the simple fact of being static, necessarily a subset of these.
When both hands are actively used for motion (as opposed to the 'weak' hand acting as a passive location for the 'dominant' hand), their motions may be parallel (both to the left or right), mirror images (approaching or separating), or alternating (180 out of phase, like legs pedaling a bicycle).
Stokoe et al. (1965) describe motion as a sequence, each segment of which is composed of one or more of the movement phonemes listed above, such as a fist moving outward while opening and then moving downward while closing again. Orientation is conflated with handshape, the combination being called a designator or dez. However, since that time there has been a variety of other approaches. Orientation is now generally considered a feature in its own right, separate from handshape. Liddell (1982) divides signs into phonological segments, which may be either movements or holds. Liddell likens this to the division of spoken language into consonants and vowels, with the Stokoe approach likened to the division of speech into syllables. For Liddell and those who follow him, each movement or hold consists of a set of the other features: Shape, orientation, location, and non-manual. A sign may consist of just a hold (that is, it may be without movement), or of movement plus a hold, or a hold plus movement, or more complex sequences. This simplifies the description of ASL morphology considerably.
While it can be approximated that there are around 150 handshapes, not all are phonemically distinct in ASL.  This is very similar to how there are hundreds of linguistically producible sounds, but only some are considered phonemically distinct in English. The seventeen ASL handshapes that are considered phonemically distinct (not considering finger spelling) are:
- the fist (the shape of the ASL letters A, S, T, or 10),
- the flat hand (the shape of B or 4),
- the spread (and sometimes clawed) hand (5 or E),
- the cupped hand (the C hand),
- thumb touching fingertips (as in O),
- a pointing index finger (as in 1, D, or Z),
- a hooked index finger (the X hand),
- a pointing pinky finger (I or J),
- the index and middle fingers together (U or H),
- the index and middle fingers apart (V or 2),
- the 'chopsticks' hand (K or P),
- the thumb and index finger apart (the L hand),
- the thumb, index, and middle finger extended (the 3 hand),
- thumb touching pinkie (6 or W),
- thumb touching index finger, other fingers extended (thumb touching index: F or 9),
- crossed fingers (the R hand), and
- the pinkie with thumb and/or index finger, or a spread hand with bent middle finger (the Y hand, 8 hand, 'devil's horns', bent middle-finger, and 'I love you'/airplane hands are allophones).
These handshapes are constrained in their interactions. For example, the 5 and F handshapes only make contact with another part of the body through the tip of the thumb, whereas the K and Y/8 handshapes only make contact through the tip of the middle finger, and the X handshape with the flexed joint of the index finger. The L hand always makes contact by means of the thumb, though contact with the index finger would be just as easy: when contact is made with the index finger, the position of the thumb is unimportant, so the same signer may sometimes use a handshape closer to a letter G, and sometimes closer to a letter L; the G shape is considered more basic, and therefore these are considered allophones of the G hand.
ASL includes both fingerspelling borrowings from English, as well as the incorporation of alphabetic letters from English words into ASL signs to distinguish related meanings of what would otherwise be covered by a single sign in ASL. For example, two hands trace a circle to mean 'a group of people'. Several kinds of groups can be specified by handshape: When made with C hands, the sign means 'class'; when made with F hands, it means 'family'.  Such signs are often referred to as initialized signs because they substitute the first initial an English word as the handshape in order to provide a more specific meaning.
When using alphabetic letters in these ways, several otherwise non-phonemic handshapes become distinctive. For example, outside fingerspelling there is but a single fist handshape, with the placement of the thumb irrelevant, but within fingerspelling the position of the thumb on the fist distinguishes the letters A, S, and T. Letter-incorporated signs which rely on such minor distinctions tend not to be stable in the long run, but they may eventually create new distinctions in the language. For example, due to signs such as 'elevator', which generally requires the E handshape, some argue that E has become phonemically distinct from the 5/claw handshape.
Fingerspelling has also given way to a class of signs known as "loan signs" or "borrowed signs."  Sometimes defined as lexicalized fingerspelling, loan signs are somewhat frequent and represent an English word which has, over time, developed a unique movement and shape.  Sometimes loan signs are not even recognized as such because they are so frequently used and their movement has become so specialized.  Loan signs are sometimes used for emphasis (like the loan sign #YES substituted for the sign YES), but sometimes represent the only form of the sign (e.g., #NO).  Probably the most commonly used example of a loan sign is the sign for NO.  In this sign, the first two fingers are fused, held out straight, and then tapped against the thumb in a repeated motion.  When broken down, it can be seen that this movement is an abbreviated way of fingerspelling N-O-N-O.  Loan signs are usually glossed as the English word in all capital letters preceded by the pound sign(#).Other commonly known loan signs include #CAR, #JOB, #BACK, #YES, and #EARLY.
Of all the possible locations on the body or in space, twelve are used to distinguish signs in ASL:
- the whole face or head,
- the upper face (forehead or brow),
- the mid face (eyes or nose),
- the lower face (chin or mouth),
- the side face (cheek, temple, or ear),
- the neck,
- the trunk (shoulders, chest, and belly),
- the upper arm,
- the forearm (including the elbow),
- the inside of the wrist,
- the back of the wrist, and
- the other (weak) hand: In this case, the weak hand may take one of the simpler handshapes listed above, such as the A, O, B, G, H, V, or L handshapes, but not others such as X or R.
In addition, the sign may be made in 'neutral' space in front of the chest (zero location).
For example, a 5 hand tapping the upper face means 'father', tapping the lower face means it 'mother', and tapping the torso (chest) it means 'fine'.
Signs may be made with two active hands, oriented in a specific way both to each other and to the body locations.
In addition to phonological location, there is also indexic location. For example, the 2nd/3rd-person pronouns point to their referent, or to a point in space (a 'locus') that's been set up to represent that referent. Directional (indexic) verbs  are similar. However, no words are distinguished by such divisions of signing space.
A referent locus may be set up by signing a noun and then pointing to a certain spot in sign space. The signer can later refer back to that noun by pointing to its associated location (that is, by using an indexic pronoun), or by incorporating the location into the motion of an indexic verb. For instance, if you point to a spot over your right shoulder when referring to your grandmother in another city, you can then mention her again by pointing over your shoulder instead of repeating 'my out-of-town grandmother'. Perhaps as many as eight loci may be productively used to distinguish pronouns in a conversation, before the speakers become overloaded, whereas English is restricted to three third-person pronouns: he, she, and they.
Nouns can be set up without the need for initially pointing by making a sign for them at a salient point in space near the signer. This is often accompanied by the facial expression that indicates a topic. (See below.) For example, when discussing football, you can sign 'college' on your left (most likely by signing 'college' in neutral space and extending the final hold to the locus you're setting up), fingerspell P-R-O at a locus on your right (that is, off to one side rather than in neutral space), and then ask whether one prefers collegiate or professional games by signing 'you like which?', with the indexic pronoun 'which' oscillating between the two loci.
Non-manual elements are extremely important to ASL syntax, more important than intonation is to English syntax. However, they are also phonemic in a small percentage of basic lexical signs. Non-manual features involve the mouth (lips, tongue, jaws, cheeks, and breath; called 'mouthing'), eyes (gaze, lids, and brows), and movement of the head. For example, the sign translated 'not yet' requires that the tongue touch the lower lip and that the head rotate slowly from side to side, in addition to the manual part of the sign. Without these features it is ill formed, and may not be understood.

### Morphology
ASL morphology is to a large extent iconic. This shows up especially well in reduplication and indexicality.
Many spoken languages have both inflectional and derivational morphology. ASL appears to have only derivational morphology (Liddell 2004). There are no inflections for tense, number, or person. Person is indicated indexically with some verbs, but the form this takes is specific to each verb, and can't be arbitrarily extended to new verbs the way verbal inflections can. A similar situation exists with verbal number.
'Mouthing' (making what appear to be speech sounds) is important for fluent signing, and it has morphological uses. For example, one may sign 'man tall' to indicate the man is tall, but by mouthing the syllable cha while signing 'tall', the phrase becomes that man is enormous!
There are other ways of modifying a verb or adjective to make it more intense. These are all more or less equivalent to adding the word "very" in English; which morphology is used depends on the word being modified. Certain words which are short in English, such as 'sad' and 'mad', are fingerspelled rather than signed to mean 'very sad' and 'very mad'. Others are reduplicated. Some signs are produced with an exaggeratedly large motion, so that they take up more sign space than normal. This may involve a back-and-forth scissoring motion of the arms to indicate that the sign ought to be yet larger, but that one is physically incapable of making it big enough. Many other signs are given a slow, tense production. The fact that this modulation is morphological rather than merely mimetic can be seen in the sign for 'fast': both 'very slow' and 'very fast' are signed by making the motion slower and more deliberate than it is in the citation forms of 'slow' and 'fast', not by making it slower for 'very slow' and faster for 'very fast'.
Reduplication (morphological repetition) is extremely common in ASL. Generally the motion of the sign is shortened as well as repeated. Nouns may be derived from verbs through reduplication. For example, the noun chair is formed from the verb to sit by repeating it with a reduced degree of motion. Similar relationships exist between acquisition and to get, airplane and to fly (on an airplane), also window and to open/close a window.
Reduplication is commonly used to express intensity as well as several verbal aspects (see below). It is also used to derive signs such as 'every two weeks' from 'two weeks', and is used for verbal number (see below), where the reduplication is iconic for the repetitive meaning of the sign.
Many ASL words are historically compounds. However, the two elements of these signs have fused, with features being lost from one or both, to create what might be better called a blend than a compound. Typically only the final hold (see above) remains from the first element, and any reduplication is lost from the second.
An example is the verb 'to agree', which derives from the two signs 'to think' and 'to be alike'. The verb 'to think' is signed by bringing a 1 hand inward and touching the forehead (a move and a hold). 'Alike' is signed by holding two 1 hands parallel, pointing outward, and bringing them together two or three times. The compound/blend 'to agree' starts as 'to think' ends: with the index finger touching the forehead (the final hold of that sign). In addition, the weak hand is already in place, in anticipation of the next part of the sign. Then the hand at the forehead is brought down parallel to the weak hand; it approaches but does not make actual contact, and there is no repetition.
Affixes are extremely common in spoken languages, which except for suprasegmental features such as tone are tightly constrained by the sequential nature of voice sounds. In ASL, however, morphemes may be expressed simultaneously, and perhaps consequently there are only a few affixes.
One of these, transcribed as '-er', is made by placing two B or 5 hands in front of the torso, palms facing each other, and lowering them. This suffix cannot occur on its own, but must follow one of a limited set of verbs, which then together with it become the sign for the performer of the action, as in 'drive-er' and 'teach-er'.
An ASL prefix, (touching the chin), is used with number signs to indicate 'years old'. The prefix completely assimilates with the initial handshape of the number. For instance, 'fifteen' is signed with a B hand that bends several times at the knuckles. The chin-touch prefix in 'fifteen years old' is thus also made with a B hand. For 'three years old', however, the prefix is made with a 3 hand.
Rather than relying on sequential affixes, ASL makes heavy use of simultaneous modification of signs. One example of this is found in the aspectual system (see below); another is numeral incorporation: There are several families of two-handed signs which require one of the hands to take the handshape of a numeral. Many of these deal with time. For example, drawing the dominant hand lengthwise across the palm and fingers of a flat B hand indicates a number of weeks; the dominant hand takes the form of a numeral from one to nine to specify how many weeks. There are analogous signs for 'weeks ago' and 'weeks from now', etc., though in practice several of these signs are only found with the lower numerals.
ASL also has a system of classifiers which may be incorporated into signs. A fist may represent an inactive object such as a rock (this is the default or neutral classifier), a horizontal Y hand may represent an aircraft, a horizontal 3 hand a motor vehicle, an upright G hand a person on foot, an upright V hand a pair of people on foot, and so on through higher numbers of people. These classifiers are moved through sign space to iconically represent the actions of their referents. For example, a Y hand may 'lift off' or 'land on' a horizontal B hand to sign an aircraft taking off or landing; a 3 hand may be brought down on a B hand to sign parking a car; and a G hand may be brought toward a V hand to represent one person approaching two.
Frames are a morphological device that may be unique to sign languages (Liddell 2004). They are incomplete sets of the features which make up signs, and they combine with existing signs, absorbing features from them to form a derived sign. It is the frame which specifies the number and nature of segments in the resulting sign, while the basic signs it combines with lose all but one or two of their original features.
One, the WEEKLY frame, consists of a simple downward movement. It combines with the signs for the days of the week, which then lose their inherent movement. For example, 'Monday' consists of an M/O hand made with a circling movement. 'MondayWEEKLY' (that is, 'on Mondays') is therefore signed as an M/O hand that drops downward, but without the circling movement. A similar DAILY frame (a sideward pan) combines with times of the day, such as 'morning' and 'afternoon', which likewise keep their handshape and location but lose their original movement. Numeral incorporation (see above) also uses frames. However, in ASL frames are most productively utilized for verbal aspect.
While there is no grammatical tense in ASL, there are numerous verbal aspects. These are produced by modulating the verb: Through reduplication, by placing the verb in an aspectual frame (see above), or with a combination of these means.
An example of an aspectual frame is the unrealized inceptive aspect ('just about to X'), illustrated here with the verb 'to tell'. 'To tell' is an indexical (directional) verb, where the index finger (a G hand) begins with a touch to the chin and then move outward to point out the recipient of the telling. 'To be just about to tell' retains just the locus and the initial chin touch, which now becomes the final hold of the sign; all other features from the basic verb (in this case, the outward motion and pointing) are dropped and replaced by features from the frame (which are shared with the unrealized inceptive aspects of other verbs such as 'look at', 'wash the dishes', 'yell', 'flirt', etc.). These frame features are: Eye gaze toward the locus (which is no longer pointed at with the hand), an open jaw, and a hand (or hands, in the case of two-hand verbs) in front of the trunk which moves in an arc to the onset location of the basic verb (in this case, touching the chin), while the trunk rotates and the signer inhales, catching her breath during the final hold. The hand shape throughout the sign is whichever is required by the final hold, in this case a G hand.
The variety of aspects in ASL can be illustrated by the verb 'to be sick', which involves the Y/8 hand touching the forehead, and which can be modified by a large number of frames. Several of these involve reduplication, which may but need not be analyzed as part of the frame. (The appropriate non-manual features are not described here.)
- stative "to be sick" is made with simple iterated contact, typically with around four iterations. This is the basic, citation form of the verb.
- inchoative "to get sick, to take sick" is made with a single straight movement to contact and a hold of the Y/8 hand on the forehead.
- predisposional "to be sickly, to be prone to get sick" is made with incomplete motion: three even circular cycles without contact. This adds reduplication to verbs such as 'to look at' which do not already contain repetition.
- susceptative "to get sick easily" is made with a thrusting motion: The onset is held; then there is a brief, tense thrust that is checked before actual contact in made.
- frequentative "to be often sick" is given a marcato articulation: A regular beat, with 4-6 iterations, and marked onsets and holds.
- susceptive and frequentive may be combined to mean "to get sick easily and often": Four brief thrusts on a marked, steady beat, without contact with the forehead.
- protractive "to be continuously sick" is made with a long, tense hold and no movement at all.
- incessant "to get sick incessantly" has a reduplicated tremolo articulation: A dozen tiny, tense, uneven iterations, as rapid as possible and without contact.
- durative "to be sick for a long time" is made with a reduplicated elliptical motion: Three slow, uneven cycles, with a heavy downward brush of the forehead and an arching return.
- iterative "to get sick over and over again" is made with three tense movements and slow returns to the onset position.
- intensive "to be very sick" in given a single tense articulation: A tense onset hold followed by a single very rapid motion to a long final hold.
- resultative "to become fully sick" (that is, a complete change of health) is made with an accelerando articulation: A single elongated tense movement which starts slowly and heavily, accelerating to a long final hold.
- approximative "to be sort of sick, to be a little sick" is made with a reduplicated lax articulation: A spacially extremely reduced, minimal movement, involving a dozen iterations without contact.
- semblitive "to appear to be sick" 
- increasing "to get more and more sick" 
These modulations readily combine with each other to create yet finer distinctions. Not all verbs take all aspects,and the forms they do take will not necessarily be completely analogous to the verb illustrated here. Conversely, not all aspects are possible with this one verb.
Aspect is unusual in ASL in that transitive verbs derived for aspect lose their transitivity. That is, while you can sign 'dog chew bone' for the dog chewed on a bone, or 'she look-at me' for she looked at me, you cannot do the same in the durative to mean the dog gnawed on the bone or she stared at me. Instead, you must use other strategies, such as a topic construction (see below) to avoid having an object for the verb.
Reduplication is also used when expressing verbal number. Verbal number indicates that the action of the verb is repeated; in the case of ASL it is apparently limited to transitive verbs, where the motion of the verb is either extended or repeated to cover multiple object or recipient loci. (Simple plurality of action can also be conveyed with reduplication, but without indexing any object loci; in fact, such aspectual forms do not allow objects, as noted above.) There are specific dual forms (and for some signers trial forms), as well as plurals. With dual objects, the motion of the verb may be made twice with one hand, or simultaneously with both; while with plurals the object loci may be taken as a group by using a single sweep of the signing hand while the verbal motion is being performed, or individuated by iterating the move across the sweep. For example, 'to ask someone a question' is signed by flexing the index finger of an upright G hand is the direction of that person; the dual involves flexing it at both object loci (sequentially with one hand or simultaneously with both), the simple plural involves a single flexing which spans the object group while the hand arcs across it, and the individuated plural involves multiple rapid flexings while the hand arcs. If the singular verb uses reduplication, that is lost in the dual and plural forms.

### Syntax
ASL syntax is primarily conveyed through a combination of word order and non-manual features. Early accounts of word order, among other issues, were often confused because non-manual features were not considered.
The basic constituent order of ASL is subject object verb. This is the order of words in a clause; however, either the subject or the object, or both, may be unexpressed in the main clause of an utterance, as ASL is a pro-drop language. In practice there is a great deal of flexibility to ASL word order, made possible by the use of topics and tags. Both are indicated with non-manual features. Within a noun phrase, the word order is noun-number and noun-adjective.
ASL does not have a copula (linking 'to be' verb). For example, my hair is wet is signed 'my hair wet', and my name is Pete may be signed 'TOPIC P-E-T-E'.
A topic sets off background information that will be discussed in the following main clause. Topic constructions are not often used in standard English, but they are common in some dialects, as in,
That dog, I never could hunt him.
In ASL, the eyebrows are raised during the production of a topic, and often a slight pause follows:
 I like lambAs for meat, I prefer lamb.
ASL utterances do not require topics, but their use is extremely common. They are used for purposes of information flow, to set up referent loci (see above), and to supply objects for verbs which are grammatically prevented from taking objects themselves (see below).
Without a topic, the dog chased my cat is signed:
dog chase my cat
However, people tend to want to set up the object of their concern first and then discuss what happened to it. In English, we do this with passive clauses: my cat was chased by the dog. In ASL, topics are used with similar effect:
TOPIC dog chaseor literallyMy cat, the dog chased it.
If the word order of the main clause is changed, the meaning of the utterance also changes:
TOPIC chase dogmeansmy cat chased the dogliterally, "My cat, it chased the dog."
Information may also be added after the main clause as a kind of 'afterthought'. In ASL this is commonly seen with subject pronouns. These are accompanied by a nod of the head, and make a statement more emphatic:
boy fall"The boy fell down."
versus
boy fall TAG"The boy fell down, he did."
The subject need not be mentioned, as in
fall"He fell down."
versus
fall TAG"He fell down, he did."
As noted above, in ASL aspectually marked verbs cannot take objects. To deal with this,  the object must be known from context so that it does not need to be further specified. This is accomplished in two ways:
- The object may be made prominent in a prior clause, or
- It may be used as the topic of the utterance at hand.
Of these two strategies, the first is the more common. For my friend was typing her term paper all night to be used with a durative aspect, this would result in
my friend type T-E-R-M paper. typeDURATIVE all-night
The less colloquial topic construction may come out as,
TOPIC, TOPIC, typeDURATIVE all-night
Negated clauses may be signaled by shaking the head during the entire clause. A topic, however, cannot be so negated; the headshake can only be produced during the production of the main clause. (A second type of negation starts with the verb and continues to the end of the clause.)
Yes-no questions are signaled by raising the eyebrows, while wh- (information) questions require a lowering of the eyebrows. Raised eyebrows  are also used for rhetorical questions which are not intended to elicit an answer.
Rhetorical questions are much more common in ASL than in English. For example, I don't like garlic may be signed,
NEGATIVE RHETORICAL, garlic
. This strategy is commonly used instead of signing the word 'because' for clarity or emphasis. For instance, I love to eat pasta because I am Italian would be signed,
I love eat pasta RHETORICAL, I Italian'
Relative clauses are signaled by tilting back the head and raising the eyebrows and upper lip. This is done during the performance of the entire clause. There is no change in word order. For example, the dog which recently chased the cat came home would be signed
RELATIVE come home
, where the brackets here indicate the duration of the non-manual features. If the sign 'recently' were made without these features, it would lie outside the relative clause, and the meaning would change to "the dog which chased the cat recently came home".

### Deixis
In ASL signers set up regions of space (loci) for specific referents (see above); these can then be referred to indexically by pointing at those locations with pronouns and indexical verbs.
Personal pronouns in ASL are indexic. That is, they point to their referent, or to a locus representing their referent. Meier 1990 demonstrates that only two grammatical persons are distinguished in ASL: First person and non-first person, as in Damin. Both persons come in several numbers as well as with signs such as 'my' and 'by myself'.
Meier provides several arguments for believing that ASL does not formally distinguish second from third person. For example, when pointing to a person that is physically present, a pronoun is equivalent to either 'you' or '(s)he' depending on the discourse. There is nothing in the sign itself, nor in the direction of eye gaze or body posture, that can be relied on to make this distinction. That is, the same formal sign can refer to any of several second or third persons, which the indexic nature of the pronoun makes clear. In English, indexic uses also occur, as in 'I need you to go to the store and you to stay here', but not so ubiquitously. In contrast,several first person ASL pronouns, such as the plural possessive ('our'), look different from their non-first person equivalents, and a couple of pronouns do not occur in the first person at all, so first and non-first persons are formally distinct.
Personal pronouns have separate forms for singular ('I' and 'you/(s)he') and plural ('we' and 'you/they'). These have possessive counterparts: 'my', 'our', 'your/his/her', 'your/their'. In addition, there are pronoun forms which incorporate numerals from two to five ('the three of us', 'the four of you/them', etc.), though the dual pronouns are slightly idiosyncratic in form (i.e., they have a K rather than 2 handshape, and the wrist nods rather than circles). These numeral-incorporated pronouns have no possessive equivalents.
Also among the personal pronouns are the 'self' forms ('by myself', 'by your/themselves', etc.). These only occur in the singular and plural (there is no numeral incorporation), and are only found as subjects. They have derived emphatic and 'characterizing' forms, with modifications used for derivation rather like those for verbal aspect. The 'characterizing' pronoun is used when describing someone who has just been mentioned. It only occurs as a non-first person singular form.
Finally there are formal pronouns used for honored guests. These occur as singular and plural in the non-first person, but only as singular in the first person.
ASL is a pro-drop language, which means that pronouns are not used when the referent is obvious from context and is not being emphasized.
Within ASL there is a class of indexical (often called 'directional') verbs. These include the signs for 'see', 'pay', 'give', 'show', 'invite', 'help', 'send', 'bite', etc. These verbs include an element of motion that indexes one or more referents, either physically present or set up through the referent locus system. If there are two loci, the first indicates the subject and the second the object, direct or indirect depending on the verb, reflecting the basic word order of ASL. For example, 'give' is a bi-indexical verb based on a flattened M/O handshape. For 'I give you', the hand moves from myself toward you; for 'you give me', it moves from you to me. 'See' is indicated with a V handshape. Two loci for a dog and a cat can be set up, with the sign moving between them to indicate 'the dog sees the cat' (if it starts at the locus for dog and moves toward the locus for cat) or 'the cat sees the dog' (with the motion in the opposite direction), or the V hand can circulate between both loci and myself to mean 'we (the dog, the cat, and myself) see each other'. The verb 'to be in pain' (index fingers pointed at each other and alternately approaching and separating) is signed at the location of the pain (head for headache, cheek for toothache, abdomen for stomachache, etc.). This is normally done in relation to the signer's own body, regardless of the person feeling the pain, but may take also use the locus system, especially for body parts which are not normally part of the sign space, such as the leg.

### Time-sequenced ordering
ASL makes heavy use of time-sequenced ordering, meaning that events are signed in the order in which they occur. For example, for I was late to class last night because my boss handed me a huge stack of work after lunch yesterday, one would sign 'yesterday lunch finish, boss give-me work big-stack, night class late-me'. In stories, however, ordering is malleable, since one can choose to sequence the events either in the order in which they occurred or in the order in which one found out about them.

# Writing systems
ASL is often written with English words in all capital letters, which is known as glossing. This is, however, a method used simply to teach the structure of the language. ASL is a visual language, not a written language. There is no one-to-one correspondence between words in ASL and English, and much of the inflectional modulation of ASL signs is lost.
There are two true writing systems in use for ASL: a phonemic Stokoe notation, which has a separate symbol or diacritic mark for every phonemic hand shape, motion, and position (though it leaves something to be desired in the representation of facial expression), and a more popular iconic system called SignWriting, which represents each sign with a rather abstract illustration of its salient features. SignWriting is commonly used for student newsletters and similar purposes.

# Baby Sign
In recent years, it has been shown that exposure to sign language has a positive impact on the socialization of hearing children.  When infants are taught to sign, parents are able to converse with them at a developmental stage when they are not yet capable of producing oral speech, which requires fine control of both breathing and the vocal tract. The ability of a child to actively communicate earlier than would otherwise be possible appears to accelerate language development and to decrease the frustrations of communication.
Many parents use a collection of simplified or ad hoc signs called "baby sign", as infants do not have the dexterity required for true ASL. However, parents can learn to recognize their baby's approximations of adult ASL signs, just as they will later learn to recognize their approximations of oral language, so teaching an infant ASL is also possible. Typically young children will make an ASL sign in the correct location and use the correct hand motion, but may be able only to approximate the hand shape, for example, using one finger instead of three in signing water.

# Primate ASL usage
ASL has been taught to both species of chimpanzee, the bonobo and common chimpanzee, as well as to gorillas, though to what extent they actually use it is debatable. Several of the animals have been said to have mastered more than one hundred signs, though there is disagreement about the primates' ability to sign. For example, the Washoe research team asked Washoe's handlers to write signs down whenever they witnessed them being produced by Washoe. The hearing signers on the team turned in long lists of signs while the only deaf native speaker of ASL on the team turned in a blank list, explaining that what she saw were not signs at all, simply gestures.  Further fomenting the controversy, the researchers in the studies of Koko and Washoe refused to share their raw data with the scientific community.  The claim that non-human primates have learned ASL, or the extent to which they are capable of learning ASL or any other natural language, is not universally accepted by linguists  including some who accept similar but better-documented claims of rudimentary language acquisition by birds.  However, the claim that chimpanzees and gorillas are somewhat capable of learning languages has generally found more support among experimental psychologists and biological scientists than linguists.  Research on the ability of primates to learn sign language continues.