I play in two games where languages are very important, and a number of other settings (such as Forgotten Realms) with an intricate and lengthy listing of languages which all relate to each other. Many times in these games characters acquire old texts they need to translate (a bit of Cthulhu mythos always seems to work its way in).
Many other times, the party needs to communicate with a person or creature who does not share their language. This is a problem.
Currently the Linguistics skill only allows you to understand a foreign language if you are able to sit down and decipher it. This is great for extensive translations, but not helpful for first encounters and bartering in a strange land.
Sense motive is an OK stop-gap, but it only imparts basic ideas and concepts. It doesn't make sense to use that to try and impart messages through languages you don't speak; it makes more sense to use SM to read body language and guess at intentions. It also doesn't make sense to use SM to communicate with someone when a linguistics skill is waiting in the wings.
Accordingly I would like to see a set of rules for communicating in Pidgin languages. It is not meant to invalidate the rules for languages, rather it is meant to be a temporary solution for characters to learn languages.
I see a DC 15 for a basic message ("need food," "walk this way," "don't go in there"), DC 20 for a complex message ("Beware the black-robed man," "At noon you should use the gem"), and DC 25+ for a working conversation or cultural idioms. My group has also been working on modifying these DCs based on root languages (you can understand Pidgin Savage Elf more easily if you understand Elven, but if you don't know Draconic any language rooted in that will be more difficult to understand).
The new linguistics skill yields a fair number of polyglot characters, but this way you can encounter new languages and worlds without having to worry about who has the Tongues spell memorized.