Estonian/-da Infinitive

Estonian features two forms of Infinitives for verbs: the -ma Infinitive and the -da Infinitive. The difference is mostly based on distinction, and the language could have evolved with only one form, but ended up with two forms which have different uses and are necessary for grammatically correct and familiar-sounding Estonian.

Forming the -da Infinitive

The -da Infinitive is one aspect of a verb that cannot otherwise be derived from the -ma Infinitve or even the plain Negative form. It can only be predicted from prior knowledge, such as memory or intuition. The -da Infinitive obeys the EKI morphological type list. We can now list this form alongside the -ma Infinitive and Negative in vocabulary:

olema - (ei) ole - .olla - to be
.teadma - tea - .teada - to know
.saama - saa - .saada - to get/to become
.kuulma - .kuule - .kuulda - to hear
.tahtma - taha - .tahta - to want
nägema - näe - näha - to see
.sööma - söö - .süüa - to eat (Exception: the -da Infinitive is pronounced as ".süüi-ja")
tulema - tule - .tulla - to come
.ostma - osta - .osta - to buy
minema - lähe - .minna - to go
.võtma - võta - .võtta - to take

Many verbs tend to follow -ma -> -da transformation. The verbs listed here now have the . emphasis dot added to them. If you pay attention to the Overlong emphasis in Estonian, you can avoid the Estonian foreign accent to some degree.

New verbs

.müüma - müü - .müüa - to sell (like "süüa", the -da Infinitive is pronounced "müüi-ja")
kaduma - kao - kaduda - to disappear
.ilmuma - .ilmu - .ilmuda - to appear
.soovima - .soovi - .soovida - to wish
helistama - helista - helistada - to call

The difference

While the semantic difference between the -ma and -da infinitive forms seems obvious to the native speaker, they find it difficult to articulate when pressed. There is, however, a fairly straightforward explanation: The -da form is used to express an action that has a hypothetical component, i.e. it may or may not actually occur.

-ma Infinitive		-da Infinitive
English	Estonian	English	Estonian
He/She must eat	Ta peab .sööma	I want to eat	Ma tahan .süüa
After verbs of motion: He/She goes to eat	Ta läheb .sööma	He/She can sell apples	Ta võib .müüa .õune Ta võib .õune .müüa
He/She comes to eat	Ta tuleb .sööma	You must want to appear (self) You must want to show up	Sa pead tahtma ilmuda Occasionally a construct like "Sa pead tahtma ilmuma" is mistakenly used but often unnoticed Sa pead ilmuda tahtma This is a complicated phrase, some native speakers might find it uncomfortable to put a -da in front of a -ma
After certain participles and adjectives: I am ready to go	Ma olen valmis minema	He/She cannot bear to do this	Ta ei .jaksa seda teha

External resources

Appendix: Secondary forms

-ma actually has 5 forms, of which the primary is the Nominative, which we've used so far to list verbs themselves, and as arguments to the verb "pidama" (to need to). The other 4 also correspond to 4 of the 14 cases. The -ma form(s) are used to describe the verb or action itself.

Nominative: teadma - to know
Inessive: teadmas - in knowing
Elative: teadmast - out of knowing, to stop knowing
Translative: teadmaks - for knowing
Abessive: teadmata - without knowing

-da has two forms: the -da and the -des. The -des is used as "while", which acts as a kind of present participle, but doesn't act as an adjective like participles do, nt: Seda teades, ta pidi seda tegema - Knowing that, he/she had to do it.