Splits, internal and external, as a window into the nature of features

Lexemes may be split internally, by phenomena such as suppletion, periphrasis, heteroclisis and deponency. Generalizing over these phenomena, which split a lexeme’s paradigm, we can establish a typology of the possible internal splits. There are also lexemes whose external requirements are split: they induce different agreement, for instance. Again, a typology of these splits has been proposed. The next logical step is to attempt a typology of the possible relations between internal and external splits. This is not straightforward, since we need to avoid spurious linkages. Four lines of argument are offered: (i) general plausibility: the internal-external linkage is compelling, and so other accounts require a degree of coincidence which is unlikely; (ii) overabundance: alternative inflectional forms link to different external requirements; (iii) variation in time and space: splits in inflection and in external requirements vary, while maintaining their linkage; (iv) pluralia tantum nouns: the different types of these nouns provide intriguing confirming evidence. Case studies include Asia Minor Greek, Polish, Russian, Scottish Gaelic, Sɛlɛɛ, Serbo-Croat (BCMS), Slovenian, Latin and Old Frisian. The clear instances which emerge, where an external split is demonstrably linked to an internal one, prove both surprising and significant. We discover that in split paradigms, besides overt overabundance, there may also be covertly overabundant cells. Furthermore, when external splits involve individual cells, these will not induce simple (consistent) agreement. This makes good sense, demonstrating that featural information is associated with lexemes in a natural default manner: at the lexeme level by default, unless overridden at the sub-paradigm level, unless in turn overridden at the level of individual cells.