that they were ejectives that became preglottalized in Italic and Balto-Slavic before losing their glottalization and becoming voiced. It is very common in the world's languages for glottal stops to drop and lengthen preceding vowels. In Quileute, for example, the sequences , , and , as found in ak’a ~ a’k’a ~ āk’a, are allophones in free variation. In Balto-Slavic, glottalization is also directly attested, in the broken tone of Latvian and Žemaitian. Dialects of Armenian also show glottalization. It has been argued to be influence from the other Caucasian languages, but Kortlandt argues glottalization cannot be considered a modern innovation and must be reconstructed with a wider dialectal distribution for older stages of Armenian. Objections The primary objection to the theory is the alleged difficulty in explaining how the sound systems of the attested dialects were derived from a parent language in the above form. If the parent language had a typologically unusual system like the traditional , it might be expected to collapse into more typical systems, possibly with different solutions in the various daughter languages, which is what one finds. For example, Indo-Aryan added an unvoiced aspirate series () and gained an element of symmetry; Greek and Italic devoiced the murmured series to a more common aspirate series ( to ); Iranian, Celtic and Balto-Slavic deaspirated the murmured series to modal voice ( to ) and Germanic and Armenian chain-shifted all three series ( > ). In each case, the attested system represents a change that could be expected from the proposed parent. If the system were typologically common, as proposed by the glottalic theory, it might be expected to be stable and so be preserved in at least some of the daughter languages, which is not the case: no daughter language preserves ejective sounds in places that the theory postulates them. Its proponents respond that if Proto-Indo-European did not have true ejectives but some less stable kind of glottalic consonant, their loss would be more understandable, but that undercuts many of the original motivations of the glottalic theory, which are based on ejectives (rather than glottalized consonants) and on the idea of a typologically natural (and so stable) system. Regardless, there are languages in which ejective consonants have voiced allophones, such as Blin and Kw'adza, which has been suggested as an "empirical precedent" for the glottalic theory. The typological underpinnings of the glottalic theory itself have