Learn Turkish: Lamba koltuğun yanında. - The lamp is next to the armchair.

In Turkish, spatial words like yan (side) act like nouns. To say "next to the armchair," you literally say "at the armchair's side." This requires the genitive (possessive) suffix on the owner, turning koltuk into koltuğun, and the possessive suffix on the location word.

I know the word for armchair is koltuk. Why does it change to koltuğun here?

This is an example of consonant mutation. When you add a suffix starting with a vowel—like the possessive suffix -un—to a word ending in k, the k softens into a ğ (yumuşak g) to make it easier to pronounce.

Let's break down yanında. What are all those suffixes doing?

The root is yan (side). The -ı is the "its" possessive suffix, making "its side". The -da is the locative suffix meaning "at". The -n- in the middle is a buffer letter. Whenever you add a location suffix (like -da) directly after a possessive suffix, you must use an -n- to separate them.

Where is the word for "is" in this sentence?

Turkish doesn't use a separate word for "is" or "are" in simple descriptive sentences like this. The "is" is naturally implied just by stating the subject (Lamba) followed by its location.