The numbering of the sentences shows as underlined dots when using \ag. \a. \b. of linguex and tipa . \bg. works fine but starts numbering from (a.)
\documentclass{article}
\usepackage{linguex}
\usepackage[main=english,italian,spanish,portuguese,catalan]{babel}
%babel has problems with french - tried frenchle does't work either
\usepackage{harvard}
\bibliographystyle{agsm}
\usepackage{tipa}
\usepackage{hyperref}
\begin{document}
\section{Catalan}
text text text text text text text text text text text text text text text text text (English)
\ex. \label{cat2}
\ag. en Joan t\'e m\'es vaques que en Pere. (NP-comparison)\\
D John have.3SG more cows than D Peter\\
John has more cows than Peter. \cite{Hualde2002}
\bg. t' estimo m\'es que la Maria.\\
CL.2s love more that the Mary\\
I love you more than Mary. \cite{Hualde2002}
\bg. en Joan \'es m\'es alt que la Maria. (AdjP-Comparison)\\
D John is more tall that D Maria\\
John is taller than Mary \cite{Hualde2002}
\section{English}
\ex. \a. This is an English example.
\b. This is an English example.
\end{document}


linguexaftertipa. However, this might cause malfunctions. – egreg Jan 04 '15 at 17:38