Weren't is a contracted form of 'were not.' It functions as a negative past tense auxiliary in statements about second-person or plural subjects, or as a hypothetical/subjunctive in some contexts. In everyday speech, it often reduces to a quick /wəːnt/ or /wɜːnt/ sound, blending vowels with the consonant cluster. Note its pronunciation is sensitive to surrounding phonemes and pace in connected speech.
Full pronunciation guide
