Learn Turkish: Akşama kadar çalışıyorum. - I am working until the evening.

The -a is the dative suffix, which usually means "to" or "towards". The word kadar (until) always requires the noun before it to take this ending. So, to say "until evening", you literally say "up to the evening".

Why is it akşama kadar and not akşame kadar?

The dative suffix follows 2-way vowel harmony, meaning it can be either -a or -e. Because the last vowel in akşam is "a" (a back vowel), we must use -a.

How do you build the verb çalışıyorum?

We start with the verb stem çalış (work). To add the present continuous suffix -yor, we need a connecting vowel because the stem ends in a consonant. Following 4-way vowel harmony, we use -ı-, making it çalışıyor (he/she/it is working). Finally, we add the personal suffix -um to mean "I", giving us çalışıyorum.

Why does kadar come after akşama?

Unlike English, which uses prepositions before a noun (like "until evening"), Turkish uses postpositions. These words always come after the noun they belong to, which is why kadar comes at the end of the phrase.