Secondary articulation
In phonetics, secondary articulation occurs when the articulation of a consonant is equivalent to the combined articulations of two or three simpler consonants, at least one of which is an approximant. The secondary articulation of such co-articulated consonants is the approximant-like articulation. It "colors" the primary articulation rather than obscuring it. Maledo (2011) defines secondary articulation as the superimposition of lesser stricture upon a primary articulation. Types. There are several kinds of secondary articulation supported by the International Phonetic Alphabet: It can sometimes be difficult to distinguish primary and secondary articulation. For example, the alveolo-palatal  consonants are sometimes characterized as a distinct primary articulation and sometimes as palatalization of postalveolar fricatives, equivalent to or . Transcription. The most common method of transcription in the IPA is to turn the letter corresponding to the secondary articulation into a superscript written "after" the letter for the primary articulation. For example, the "w" in is written after the "k". This can be misleading, as it iconically suggests that the is released into a sound, analogous to ([k] with a lateral and nasal release), when actually the two articulations of are generally pronounced more-or-less simultaneously. Secondary articulation often  has a strong effect on surrounding vowels, and may have an audible realization that precedes the primary consonant, or both precedes and follows it. For example, will not generally sound simply like , but may be closer to or even . For this reason, the IPA symbols for labialization and palatalization were for a time placed under the primary letter (e.g. for and for ), and a number of phoneticians still prefer such unambiguous usage, with and used specifically for off-glides, despite the official policy of the IPA. In the official IPA there remains only an alternative symbol for velarization/pharyngealizaton that  is superposed over the primary (e.g. for dark L), but that has font support for a limited number of consonants and is inadvisable for others, where it can be illegible. A few phoneticians use superscript letters for offglides and "subscript" letters for simultaneous articulation (e.g. vs ). There is a longstanding tradition in the IPA that one may turn "any" IPA letter into a superscript, and in so doing impart its features to the base consonant. For instance, would be an articulation of that has qualities of . However, the features are not necessarily imparted as secondary articulation. Superscripts are also used  iconically to indicate the onset or release of a consonant, the on-glide or off-glide of a vowel, and fleeting or weak segments. Among other things, these phenomena include pre-nasalization (), pre-stopping (), affrication (), pre-affrication (), trilled, fricative, nasal, and lateral release (), rhoticization (), and diphthongs (). So, while indicates velarization of non-velar consonants, it is also used for fricative release of the velar stop (). Mixed consonant-vowels may indicate a transition: may be the allophone of with the transition from that identifies the consonant, while may be the allophone of before , or the formants of anticipated in the . The  2015 edition of the Extensions to the International Phonetic Alphabet formally advocates superscript letters for the first time since 1989, specifically for the release of plosives.