Learn Turkish: Yaşlı adam bir taksi bekliyor. - The old man is waiting for a taxi.

This happens because of a rule called 'vowel narrowing.' When a verb stem ends in the wide vowels a or e, and you add the present continuous -iyor suffix, that final vowel 'narrows' into ı, i, u, or ü. Because the preceding vowel in bekle- is an e, the final e changes to i to match it, giving us bekliyor.

The translation says 'waiting for a taxi'. Where is the word for 'for'?

Turkish doesn't use a separate word for 'for' with the verb beklemek (to wait). You just put the thing you are waiting for directly in front of the verb. So, bir taksi bekliyor literally translates to 'is waiting a taxi'.

Why don't we need the pronoun 'o' (he) in this sentence?

Because yaşlı adam (the old man) is already the subject! You only need to use o if you are replacing the noun entirely (like saying 'He is waiting for a taxi'). The verb bekliyor on its own also has no personal ending after -yor, which automatically points to a third-person subject ('he', 'she', or 'it').

Does the word yaşlı work for anything that is old?