Glycosyltransferase that specifically catalyzes galactosylation of cytoplasmic tRNA(Tyr) modified with queuosine at position 34 (queuosine(34)) (PubMed:37992713). Galactosylates the cyclopentene hydroxyl group of queuosine(34) in tRNA(Tyr) to form galactosyl-queuosine(34) (PubMed:37992713). Mannosylation of queuosine(34) in tRNA(Tyr) is required to slow-down elongation at cognate codons UAC and suppress stop codon readthrough, thereby regulating protein translation (PubMed:37992713). . This is the function of QTGAL (queuosine-tRNA galactosyltransferase, Ensembl gene identifier ENSG00000175711).