Learn Finnish: Kun edistys on nopeaa, me tunnemme itsemme aikaansaaviksi ja hyväksytyiksi. - When progress is fast, we feel accomplished and accepted.

When using tuntea (to feel) with a reflexive pronoun like itsemme, the adjective describing the feeling must be in the translative (-ksi) or essive (-na) case. The translative is the standard choice for subjective emotional states and conditions, which is why we use it for feeling accomplished and accepted here.

Why do aikaansaaviksi and hyväksytyiksi have the plural -i- marker?

The adjectives describe the subject of the sentence. Since the subject is the plural me (we), the adjectives must agree in number, requiring the plural marker -i- right before the translative -ksi ending.

Why is the reflexive pronoun itsemme rather than itsensä?

The reflexive pronoun must match the person of the subject. Since the subject is me (we), the base word itse takes the first-person plural possessive suffix -mme. The third-person form itsensä would only be used if the subject were he, she, or they.

Why is the adjective nopeaa in the partitive case rather than the nominative nopea?

The subject of that clause, edistys (progress), is an abstract, uncountable noun. In Finnish, when a predicative adjective describes an uncountable or abstract subject, the adjective must be in the partitive case.