Letters and habits worth unlearning

Serbian has no ъ, ь, ы, э, ё, щ, я or ю - letters that exist in some other Cyrillic-using alphabets to show a /j/ glide before a vowel. Serbian simply writes a separate letter ј before the plain vowel instead: ја, је, јо, ју - so јеж (hedgehog) spells the glide with ј before е, and ја (I) does the same before а.

Serbian also has letters with no obvious counterpart in every other Cyrillic-using alphabet: ч and ћ are a hard/soft pair close to English ch in cheap, and џ and ђ are the equivalent hard/soft pair close to English j in jungle and jam - ђ and ћ themselves differ only in voicing, not hardness. It is easy to collapse ч and ћ, or џ and ђ, into one sound out of habit - they are genuinely different letters in Serbian and can change a word's meaning.

Finally, Serbian spelling never reduces unstressed vowels the way some languages do (an unstressed о sounding like а) - always write the vowel that belongs to the word, regardless of stress: говори (speaks), never говари.