You can only be kidding or You must be joking may be English equivalents of 'Você só pode 'tah de brincadeira, n'é'. The subject pronoun 'você'means 'you'. The adverb 'só' means 'only, just'. The verb 'pode' means '[you/he/she/it] can'. The word 'tah' is a shortened form of 'estar', which means 'to be, to stand'. The preposition 'de' means ' of, from' or more loosely 'like, as'. The feminine noun 'brincadeira' means 'toy, party, joke'. The word 'n'é' is a shortened form of 'não é', which means 'is it not'. All together, they're pronounced 'voh-SEH saw paw-djee-tah djee breen-kuh-DEH-ruh neh'.