ScottOK, so I'm still not really getting the usefulness of the local and federated timelines when you can't filter them on the languages you can read.
Mr. Encyclopedia@Scott_w since language filtering is so broken it seems the best option is to filter out the primarily foreign instances. To do this from the desktop site pick a profile from the instance you want to filter and click on the "..." Next to "toots/toots and replies/media" at the bottom of the menu under the mute and block options will be an option to ignore all content from that instance.
It sucks that this is the only way to do it but it makes the federated timeline a lot more manageable.