# -iainen
## Finnish
### Etymology

-ja +‎ -inen. The suffix is spelled inconsistently as either -iainen or -jainen depending on the root word.
* -jainen is the original form of the suffix, while the former contains a preceding -i- (including those that derive from an underlying -e-), with the -j- not spelled as a result. In the past, a similar kind of vacillation occurred in the spelling of -ja derivatives, although they eventually settled into a spelling in which the -j- was always spelled (tulija, pro tulia). However, that development did not extend to this suffix, as its origin had by then been forgotten.
* A regular derivative of many verbs would have a long vowel, as it is part of the stem; thus, avajaiset should more correctly be *avaajaiset. The shortening may be by analogy.
* The use of the suffix in diminutive, often vulgar, nouns, such as those for insects, appears to follow the example of ampiainen, tuuliainen, but -ias may have also served as an inspiration.

### Suffix

-iainen (front vowel harmony variant -iäinen, linguistic notation -iAinen)
* Forms certain nouns.
    ‎tulla (“to come”) + ‎-iainen → ‎tuliainen (“souvenir”)
* (in the plural) Forms names of ceremonies from verbs or nouns.
    ‎avata (“to open”) + ‎-iainen → ‎avajaiset (“opening”)
    ‎haudata (“to bury”) + ‎-iainen → ‎hautajaiset (“funeral”)
    ‎fuksi (“university freshman”) + ‎-iainen → ‎fuksiaiset (“initiation ritual event in a university”)
* Forms certain nouns, particularly vulgar nouns or names of insects.
    ‎paska (“shit”) + ‎-iainen → ‎paskiainen (“bastard, asshole”)
    ‎muta (“mud”) + ‎-iainen → ‎mutiainen (“dark-skinned person”)
    ‎kuori (“crust”) + ‎-iainen → ‎kuoriainen (“beetle”)
    ‎ripsi (“cilium”) + ‎-iainen → ‎ripsiäinen (“thrips”)

#### Declension

Possessive forms of -iainen (Kotus type 38/nainen, no gradation) :
first-person singular possessor
singular
plural
nominative
-iaiseni
-iaiseni
accusative
nom.
-iaiseni
-iaiseni
gen.
-iaiseni
genitive
-iaiseni
-iaisteni -iaisieni
partitive
-iaistani
-iaisiani
inessive
-iaisessani
-iaisissani
elative
-iaisestani
-iaisistani
illative
-iaiseeni
-iaisiini
adessive
-iaisellani
-iaisillani
ablative
-iaiseltani
-iaisiltani
allative
-iaiselleni
-iaisilleni
essive
-iaisenani
-iaisinani
translative
-iaisekseni
-iaisikseni
abessive
-iaisettani
-iaisittani
instructive
comitative
—-iaisineni
second-person singular possessor
singular
plural
nominative
-iaisesi
-iaisesi
accusative
nom.
-iaisesi
-iaisesi
gen.
-iaisesi
genitive
-iaisesi
-iaistesi -iaisiesi
partitive
-iaistasi
-iaisiasi
inessive
-iaisessasi
-iaisissasi
elative
-iaisestasi
-iaisistasi
illative
-iaiseesi
-iaisiisi
adessive
-iaisellasi
-iaisillasi
ablative
-iaiseltasi
-iaisiltasi
allative
-iaisellesi
-iaisillesi
essive
-iaisenasi
-iaisinasi
translative
-iaiseksesi
-iaisiksesi
abessive
-iaisettasi
-iaisittasi
instructive
comitative
—-iaisinesi
first-person plural possessor
singular
plural
nominative
-iaisemme
-iaisemme
accusative
nom.
-iaisemme
-iaisemme
gen.
-iaisemme
genitive
-iaisemme
-iaistemme -iaisiemme
partitive
-iaistamme
-iaisiamme
inessive
-iaisessamme
-iaisissamme
elative
-iaisestamme
-iaisistamme
illative
-iaiseemme
-iaisiimme
adessive
-iaisellamme
-iaisillamme
ablative
-iaiseltamme
-iaisiltamme
allative
-iaisellemme
-iaisillemme
essive
-iaisenamme
-iaisinamme
translative
-iaiseksemme
-iaisiksemme
abessive
-iaisettamme
-iaisittamme
instructive
comitative
—-iaisinemme
second-person plural possessor
singular
plural
nominative
-iaisenne
-iaisenne
accusative
nom.
-iaisenne
-iaisenne
gen.
-iaisenne
genitive
-iaisenne
-iaistenne -iaisienne
partitive
-iaistanne
-iaisianne
inessive
-iaisessanne
-iaisissanne
elative
-iaisestanne
-iaisistanne
illative
-iaiseenne
-iaisiinne
adessive
-iaisellanne
-iaisillanne
ablative
-iaiseltanne
-iaisiltanne
allative
-iaisellenne
-iaisillenne
essive
-iaisenanne
-iaisinanne
translative
-iaiseksenne
-iaisiksenne
abessive
-iaisettanne
-iaisittanne
instructive
comitative
—-iaisinenne
third-person possessor
singular
plural
nominative
-iaisensa
-iaisensa
accusative
nom.
-iaisensa
-iaisensa
gen.
-iaisensa
genitive
-iaisensa
-iaistensa -iaisiensa
partitive
-iaistaan -iaistansa
-iaisiaan -iaisiansa
inessive
-iaisessaan -iaisessansa
-iaisissaan -iaisissansa
elative
-iaisestaan -iaisestansa
-iaisistaan -iaisistansa
illative
-iaiseensa
-iaisiinsa
adessive
-iaisellaan -iaisellansa
-iaisillaan -iaisillansa
ablative
-iaiseltaan -iaiseltansa
-iaisiltaan -iaisiltansa
allative
-iaiselleen -iaisellensa
-iaisilleen -iaisillensa
essive
-iaisenaan -iaisenansa
-iaisinaan -iaisinansa
translative
-iaisekseen -iaiseksensa
-iaisikseen -iaisiksensa
abessive
-iaisettaan -iaisettansa
-iaisittaan -iaisittansa
instructive
comitative
—-iaisineen -iaisinensa :

#### Derived terms
### References

* Hakulinen, Lauri. 1941–2000. Suomen kielen rakenne ja kehitys ('The Structure and Development of the Finnish Language'). Helsinki: Otava/Helsingin yliopisto.