The Western group of Tlaliolz dialects are sufficiently unlike Eastern that some would call them distinct languages, although very closely related ones. The degree of their difference might be compared to that between Norwegian and Swedish - substantial, but speakers can still learn to get by in the other variety with relative ease.
Following is a list of differences between the two dialects.
- Vowels in Western do not shorten when in sequence with another.
- The rule deleting preconsonantal sonorants in favor of long vowels has remained active in Western, continuing to apply to new words and across morpheme boundaries.
- Eastern [ae] and [ao] diphthongs are reflected instead as bisyllabic sequences [oe] and [eo].
- Eastern [ɸ] is instead reflected as [h].
- Eastern [tɬ] is instead reflected as [θ].
- All stops but /t/ collapse into [h] before another stop; /t/ instead merges into [θ] in this environment. These rules remain active in morphophonemic alternations.
- Eastern sequences of [ie] and [ei] have merged into Western /ī/ and /ē/ respectively.
- In Western, /u ū/ have collapsed into /o ō/.
- Stress in Western is consistently located on the second syllable.
- Ejectives immediately after a vowel with primary stress collapse to [ʔ] and [ʔʷ].
- Eastern /z/ corresponds to Western [ʐ] - a voiced retroflex sibilant.
- Eastern [w] corresponds to Western [gʷ], which still patterns with sonorants (e.g. it doesn't trigger plosive-conditioned rules).
- Initial and final approximant hardening (of /l j/) in Eastern does not happen in Western.
- An ejective [tʼ] has been gained in some loanwords from an unknown source.