You might be getting thrown by the fact that in the dialects different forms are used for some words, not just different pronunciations of the same form. In the Standard, however, only one form is usually permitted, but people go on pronouncing their own dialectal form. "Tuilleadh" is an example of this. The form used in Ulster Irish is actually "tilleadh", with a slender "t". It is pronounced /ˈtʃɪʎu/ (CHIL-yoo). When people write the Standard "tuilleadh" but pronounce the dialectal "tilleadh", it's understandable that you might wonder how a broad "t" can be pronounced /tʃ/. Final "-adh" is regularly pronounced /u/ in Ulster (except when it occurs on verbs immediately before a subject pronoun beginning with "s-", in which case it is pronounced /ət/, e.g. "íosfadh sé" /iːsət ʃɛ/ but "íosfadh an madadh" /iːsu ə madu/); in Connacht and Munster, however, it is pronounced /ə/ (except in certain verb endings, when it is pronounced /əx/, e.g. "íosfadh sé" /iːsəx ʃeː/). Listening to the pronunciations on focloir.ie, it seems that in Connacht as well the form is "tilleadh" (though palatalisation of "t" and "d" is less extreme in Connacht than it is in Ulster). Munster Irish doesn't distinguish between "l" and "ll", whereas Ulster Irish and some dialects of Connacht Irish do.