Learn Turkish: Bu öğretmen. - This is a teacher.

In Turkish, there is no separate word for "is" when talking about a third person or object (he, she, it, or this). The "is" is simply understood from the context. So, Bu öğretmen literally looks like "This teacher," but as a complete sentence, it means "This is a teacher."

Why isn't there a word for "a" before teacher?

In Turkish, you often drop the word bir (a/an) when simply stating what someone or something is, especially with professions. You could say Bu bir öğretmen, but Bu öğretmen is very natural and common.

Could Bu öğretmen also just mean "This teacher"?

Yes! Because there is no visible "is", Bu öğretmen can mean either the complete sentence "This is a teacher" or the phrase "This teacher" (like in "This teacher is nice"). When spoken, a slight pause after Bu helps show it means "This is a teacher". In writing, the period at the end gives it away as a full statement.