Learn Turkish: Öğrenci okulda. - The student is at school.

In Turkish, words like 'in', 'on', and 'at' aren't separate words. Instead, you add the locative suffix -da (or -de) to the end of the noun. So, okul (school) + -da (at) becomes okulda.

Why did we use -da here instead of -de?

It's because of 2-way vowel harmony. The last vowel in okul is 'u', which is a back vowel. Suffixes attaching to words with back vowels take the -a form, so we use -da.

Where is the verb 'is' in this sentence?

Turkish doesn't have a direct equivalent for the basic 'to be' verb (is/am/are) in the present tense for third-person subjects (like 'the student'). Just putting the subject (öğrenci) and the location (okulda) together is enough to form a complete sentence.

Why doesn't the sentence start with a word for 'the'?

Turkish does not have a definite article like the English word 'the'. When a noun is the subject of a sentence, like öğrenci is here, it is naturally understood as specific ('the student') rather than general ('a student') based on the context.