libfst-dev binary package in Ubuntu Bionic i386

 OpenFst is a library for constructing, combining, optimizing, and searching
 weighted finite-state transducers (FSTs). Weighted finite-state transducers
 are automata where each transition has an input label, an output label, and a
 weight. The more familiar finite-state acceptor is represented as a transducer
 with each transition's input and output label equal. Finite-state acceptors
 are used to represent sets of strings (specifically, regular or rational
 sets); finite-state transducers are used to represent binary relations between
 pairs of strings (specifically, rational transductions). The weights can be
 used to represent the cost of taking a particular transition.
 .
 This package contains the development support files.

Source package