I have a houseplant that kinda looks almost identical a little banana tree, I read somewhere that if you eat the sap, your tongue will be paralized for three days. I don't know the name of the plant.

I know a dumb cane can do this to you if eaten. It can kill a small pet so best not to have it and a pet in the house together. There are several house plants that are poisoinous that they sell in local nurseries. The poinsettas we by at the holidays are also an example of a poisoinous plant. I have never heard of the sap of a banana tree doing this to you.

how can you look something up if you dont know the name of it.

i wouldnt try it if i was you lol

Perhaps you're thinking of a mother-in-laws tongue or an elephant ear plant. Both, I've been told will do this. But, I can't really say that either really looks like a banana tree plant.