It is demonstrated that a componential code emerges when a self-organi
sing neural network is exposed to continuous speech. The code's compon
ents correspond to substructures that occur relatively independently o
f one another: words and phones. A capability for generalisation and d
iscrimination develops without having been optimised explicitly. The c
omponential structure is revealed by optimising a necessarily complica
ted nonlinear moment of the data's distribution, equal to the mean-squ
ared output response of a multi-layered network of simple threshold ne
urons. Earlier analytical work had predicted that componential codes,
generalisation and discrimination should emerge from the self-organisa
tion of threshold neurons of this form, assuming certain properties of
the pattern-space distribution of the data.