Learn Hardcore Turkish: Ben gümrükte bekliyorum.

In Turkish the verb ending already shows the subject. Bekliyorum ends with -um, which marks 1st person singular (“I”). Because of this you can drop Ben unless you want extra emphasis. So Gümrükte bekliyorum is perfectly natural.

What does the suffix -te in gümrükte indicate?

The suffix -te is the locative case marker, meaning “at” or “in.” It turns gümrük (“customs”) into gümrükte, literally “at the customs.”

Why -te and not -da, -de or -ta?

Turkish locative follows two harmony rules:

Consonant harmony: after voiceless consonants (p, t, k, ç) you use -t- rather than -d-. Gümrük ends in k, so we pick -t.
Vowel harmony: gümrük has front vowels, so we use the front vowel form -e. Together this gives -te.

Why doesn’t Turkish use an article like “the” or “a” in gümrükte?

Turkish has no definite or indefinite articles. Nouns stand alone and context tells you whether something is “a” or “the.” So gümrükte can mean “at customs,” without any extra word.

What does the in do?