Question: When is it okay to use the salitang ugat as a verb? Some verbs that aren't considered pseudo can seemingly sometimes function as such. I've noticed that they're usually used for expressions and commands. For example: a) Kain tayo! b) Punta ka rito! c) Dali, takbo! d) Labas! Is this a case of being more casual? Dropping the normal affix? (Though, "Dali, tumakbo!" and "Lumabas!" don't sound right without subjects.)
It's a casual thing. However, you have to be careful with using this form. Stick to proper grammar if you're unsure because you might end up sounding like speaking broken Tagalog. Kain tayo is acceptable but not Kain ako isda.