In בבא מציעא דף ק''ד we have this idea of דורשין לשון הדיוט. What does that mean there? The גמרא there understands this to mean we can't take a משכון that has a larger value than the הלוואה itself. Why not? It seems to me the reason is we take the משכון out of the category of being a משכון to being bought. But that does not seem to fit the גמרא in שבועות in which the משכון if taken not at the time of הלוואה is automatically bought and owned. It is rather the משכון taken at the time of the הלוואה that רבי אליעזר and רבי עקיבא disagree about and we go by רבי עקיבא that he is considered a שומר שכר. And the רי''ף says in all cases he is a שומר שכר. So דורשין לשון הדיוט seems to be ambiguous. You could say it means we take even the הלוואה taken at the time of the הלוואה and consider it owned and not just as a משכון. I mean that even רבי עקיבא and רבי אליעזר would agree that because of דורשין that it too would be considered bought and owned until the לווה pays back the חוב. The other way to understand this is to say that דורשין לשון הדיוט tells us to take what was a normal משכון which is already considered bought and owned and make it into a משכון that the מלווה is just a שומר שכר for. This last way fits the רי''ף in שבועות. But it does not fit the גמרא in בבא מציעא
