Despite the baby's-first-words title, there's not much that's new on the sixth album from college radio's favorite Austinites. Beginning with the clipped consonants and staccato feedback bursts of ''Don't Make Me a Target,'' Ga Ga Ga Ga Ga is one of those ''taking stock'' records that collates and refines everything that came before. But what an inventory of sounds they've built: an arsenal of hand claps, Motown- lifted tambourine bursts, music-hall piano lines, and bass levels that hover in the red. If it ain't broke... A-