coming from the Kähler potential.]{}

Introduction {#sec:intro}
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The origin of the structure of the fermion Yukawa couplings is one of the most intriguing puzzles left unanswered by the Standard Model. The hierarchical pattern of fermion masses and quark mixing angles strongly suggests the existence of a spontaneously broken family symmetry with the order parameter of breaking (the vacuum expectation value (vev) of one or more scalar familon fields) providing the small expansion parameter(s). This has been the most popular strategy to try to improve our understanding of the flavour structures in nature. In this scheme the (usually Supersymmetric) Standard Model is extended by a gauge or global family symmetry $G_{F}$ which is then spontaneously broken. The Yukawa couplings (or just those associated with the two lighter generations) are not allowed in the limit of unbroken family symmetry but are filled in by higher dimension operators involving powers of the familon field(s). Thus below the scale of $G_{F}$ breaking, we have an effective theory resembling the Supersymmetric Standard Model where the Yukawa couplings (with the possible exception of the third family) and all the different flavour structures are given by non-renormalisable operators in the superpotential of the kind, $$\psi \psi^{c}H\left( 