Learn Turkish: Savaştan beri her şey çok pahalı. - Everything has been very expensive since the war.

The postposition beri (since) requires the noun before it to take the ablative case suffix (-dan/-den), which usually means 'from'. So, to say 'since the war' in Turkish, you literally say 'from the war since'.

Why does the ablative suffix look like -tan here instead of the usual -dan?

This is due to consonant mutation. The word savaş (war) ends in ş, which is a voiceless consonant. When you add a suffix starting with d to a voiceless consonant, the d hardens into a t. Therefore, -dan becomes -tan.

The English translation uses 'has been', but the Turkish sentence just ends with the adjective pahalı (expensive). How does that work?

In Turkish, if a situation started in the past and is still happening right now, you usually just use the present tense. Because savaştan beri tells us when it started, simply saying pahalı (it is expensive) covers the 'has been' meaning perfectly without needing a past tense verb.

Is her şey always written as two separate words?