Local (first order) sentences, introduced by Ressayre, enjoy very nice
decidability properties, following from some stretching theorems stating some
remarkable links between the finite and the infinite model theory of these
sentences. We prove here several additional results on local sentences. The
first one is a new decidability result in the case of local sentences whose
function symbols are at most unary: one can decide, for every regular cardinal
k whether a local sentence phi has a model of order type k. Secondly we show
that this result can not be extended to the general case. Assuming the
consistency of an inaccessible cardinal we prove that the set of local
sentences having a model of order type omega_2 is not determined by the
axiomatic system ZFC + GCH, where GCH is the generalized continuum hypothesi