Fronting, backing, lowering of central vowels

The central vowels [ə] and [Λ] merge with [e], [o] or [a] by fronting, backing or lowering. This is partly determined by context:

Fronting to [e] (a context-free change, but applies especially to long and syllable-final central vowels):

Backing to [o] before [l] (a context-sensitive change: [əl] > [ol]):

Lowering to [a] before etymological [r] (often context-sensitive: [er] > [a]):

While backing before [l] and lowering before [r] is largely predictable, some contexts are not. For instance, there are several changes possible before [n]:

The remaining short vowels become low central.