The suffix of the adessive is always lla or llä in standard Finnish, e.g. talo : talo|lla : talo|i|lla, mies : miehe|llä : mieh|i|llä. In dialects and other forms of spoken language, the suffix may appear as shortened to ll or l, e.g. talol.
The adessive has several uses, including
Thus, the adessive is a case with many meanings. In analyzing a sentence, you may need to postpone the study of adessive forms to a point where you have analyzed most of the other words, to establish a context for the interpretation.
Much of the use of the adessive corresponds to the English preposition “with”, or maybe “by”. The use of the adessive for expressing tool or method has always been accepted, but there has been a lot of debate about the suitability of use where the adessive expresses just a manner or mode or even corresponds to “accompanied with”.
It has been argued that usage like ilolla are imitations of foreign expressions. However, in many contexts, it is difficult to find good replacements. For example, the word iloisesti (an sti adverb derivation of iloinen : iloisen “merry”) would be accepted by all, but it is longer than ilolla and does not quite mean the same thing. The language authorities have now widely accepted uses of the adessive such as ilolla.
Expressions such as “coffee with cream” have no simple equivalent in Finnish. Although kahvi kerman kanssa would be a literal translation, “good Finnish” as recommended in old guides uses phrases like kerman kanssa only as an adverbial relating to a verb, not as an attribute of a noun. Sometimes kera, an otherwise dated synonym for kanssa, is suggested, but kahvi kerman kera has not been used much.
Most often, people just say and write kahvi kermalla and similarly lohta sienikastikkeella (salmon with mushroom sauce) etc. when expressing things served or used with some add-on. Previously, expressions like kahvi ja kerma (coffee and cream) were recommended in language guides instead of kahvi kermalla. Such recommendations have had little effect.
However, extending the use of the adessive as an attribute to other contexts may still be regarded as substandard—and a frequent source of language jokes. People understand what myydään huoneisto parvekkeella means: a flat with a balcony is being sold; yet it can be jocularly misinterpreted as referring to a flat on a balcony or other ways. Here huoneisto ja parveke would be unacceptable, since the balcony is sold as part of the flat. Thus, in formal style, a relative clause is needed: huoneisto, jossa on parveke.
According to old style guides, the use of adessive for vehicles was restricted to situations where you controlled the vehicle, using it as an instrument. You would say menin sinne autolla (I traveled there by car) when you drove the car, but menin sinne autossa, if you just rode the car. Such distinctions are not made any more; you can say autolla even when you were just a passenger. It is, however, possible to say autossa, too, when you think of a car as an environment.
The adessive also expresses the quantity of a change, e.g. Asukasluku kasvoi tuhannella (The population increased by one thousand). This, and the use of cases of an object for similar purposes, is described in section Object-like quantifiers .