The Proto-Slavic clusters *kť/tj and *dj become palatal ķ and ģ in Mk but produce the clusters št and žd in Bg. So ‘night’ is Mk noķ, Bg nošt, srb nok.

The vowel *ě (jat) becomes e in Mk as in the Western Bg dialects, but alternates between ja (’a) and e in Standard Bg as in the Eastern dialects. So ‘snow’ is Mk sneg, Bg snjag, Srb sneg.

Schwa is a full-fledged vowel in Bg but not in Mk, where it often corresponds to other vowels, or is pronounced but not written.

Literary Mk has fixed stress on the antepenultimate vowel; in Bg stress is free.

The forms of the definite article in Mk (and some Southern Bg dialects, but not Standard Bg) distinguish three degrees of remoteness: Mk kuķava, kuķata, kuķana ‘this house, the house, that house’, Bg only kəštata ‘the house’.

Clitics (short forms of pronouns) are always in second position in the sentence (and the noun phrase) in Bg; in Mk they can start a sentence.

Regarding basic vocabulary, Standard Bg is based on the Eastern dialects, whereas Mk is closer to Western Bg.

Mk has borrowed much non-basic vocabulary from Serbo-Croat (and perhaps less from Russian than Bg has done).

So is Srbian a Bulgarian dialect?