t’ > ’d > d > dʰ > tʰ, also t > d > t > tʰ". This is the same as the compromise viewpoint to see the original formulation of glottalic theory, with ejective stops, as representing an earlier stage in the history of Proto-Indo-European, which would have undergone a period of internal evolution into a stage featuring unstable voiced glottalized stops before it branched out into the daughter languages. However, this reveals a hidden problem with Kortlandt suggesting that "voiced aspirate was probably not in Indo-European before the division into the branches" in suggesting that the absence of direct evidence for voiced aspirate losing its aspiration in "all languages except Indic, Greek and Italic" outside of Kümmel's monograph proves that it never happened because voiced aspirate probably never existed in these languages in the first place. Phonological shifts can reverse, especially after they become non-productive, which Icelandic shows much direct evidence of. The argument also contradicts Kortlandt's own supposition that the t’ > ’d sound change that occurred "except in Anatolian and Tocharian" reversed in Armenian, not to mention that the voiced "stops" shifted from the traditional voiced aspirates in Proto-Germanic regularly alternated with fricatives. If voiced aspirates ever existed at an ancient stage of any Indo-European languages other than Indic, they could have easily become fricatives either phonemically, as in Italic and ultimately in Greek, or allophonically, as in Germanic. This direct evidence for the ease of occurrence for such a development renders Kortlandt's view that the two voiced series must have, however partially, collapsed back into one, in Albanian and Iranian something of a paradox. The paradox goes even deeper, many apparent instances of preglottalized stops in Kortlandt's view of late Proto-Indo-European may have been the result of a metathesis 'V/ʔV→V'/Vʔ equally to C'/Cʔ→'C/ʔC. The solution to this paradox is that the Proto-Indo-European glottalic series was never fully stable ejectives, first splitting into ejectives and geminates and then allophonically varying rather freely as ejectives and preglottalized stops. Lexical accent Since the traditional reconstruction of Proto-Indo-European includes one stress per word, generally on the root or stem of the word, and the non-representation of voiced-voiced and voiceless-voiced aspirated stop sequences in the reconstructed roots is not a real problem; modern reconstructions including glottalic phonemes are making an unnecessarily strong assumption. If Proto-Indo-European words can only have one stress each and in many languages that have glottalized consonants