Learn Turkish: Öğrenci kütüphanede sakız çiğniyorsa kurallara uymuyor. - If the student is chewing gum in the library, he is not following the rules.

This combines the present continuous suffix -iyor with the conditional suffix -sa (if). So, çiğniyor (is chewing) + -sa (if) becomes çiğniyorsa (if he/she is chewing). Since -iyor always ends in the consonant 'r', you just attach -sa directly without needing a buffer 'y'.

The dictionary word for "chew" is çiğnemek. Why does it become çiğniyor with an 'i'?

This is an example of vowel narrowing. The verb root is çiğne- (chew). When you add the -iyor suffix to a verb ending in 'a' or 'e', that final vowel shrinks down to 'ı', 'i', 'u', or 'ü'. Because of vowel harmony with the 'i' earlier in the word, the 'e' narrows to 'i', giving us çiğniyor.

Why is there an -a on the end of kurallara (rules)?

The verb uymak (to fit, to comply, to follow) requires the dative case (the "to/for" direction). In English we simply "follow the rules," but in Turkish you technically "comply to the rules." That's why we add the dative suffix -a to kurallar (rules), making it kurallara.

How does the negative work in uymuyor?