Do inputs need to be restricted on a language-specific basis? Classic Optimality Theory claims that they do not: the rich base is filtered by constraints that yield full contrast, complementary distributions or positional neutralisation depending on the ranking. The problem arises when positional neutralisation affects a gappy contrast. In Russian, voicing neutralisation works on all obstruents alike, including non-contrastively voiceless ones – but it creates voiced allophones that are otherwise disallowed. In the popular OT account of positional neutralisation, analysing these cases requires handling voicing twice: once for all segments, then again for gaps. I argue that the solution is to relax the rich base assumption by ruling gaps out at the UR level through morpheme structure constraints (Halle 1959 et seq.).

In Tamil, coronals are licensed in onsets and initial syllables, exemplifying what Jesney (2011b) calls Licensing in Multiple Contexts (LMC). Jesney shows that while only positional faithfulness produces LMC in Optimality Theory, positional licensing provides a competing analysis of LMC in Harmonic Grammar (HG). This suggests that positional faithfulness may not be necessary in HG. We argue, though, that positional faithfulness remains essential. First, other facts in Tamil are incompatible with the positional licensing approach to LMC, rendering the positional faithfulness alternative the only viable analysis. Second, only with positional faithfulness can certain typological generalizations concerning assimilation between consonants be captured.