Lots of verbs in Yiddish have associated adverbs attached to them. For equivalent English example, take and take on have quite different meanings, as do pay and pay back. These added words are usually added on to the beginning of the word in infinitive form, and to the end in conjugated form. Here are a few examples.
The Rashba quotes the Ramban and adds a few words.
Another word which is commonly added to Yiddish verbs is the word זיך (pronounced zach or zich). It is always the next word after a verb, and it makes the verb before it passive. For example, עסן means to eat. עסן זיך means to be eaten.
אַ נײַ װאָרט - A new word
זיך (pronounced זאַך)
װאָס הערט זיך?
What's up? (literally, what is heard, which is the source of the Hebrew expression מה נשמע?)
דאָס רופֿט זיך אָן גירי דיליה.
This is called (from the verb אָנרופֿן, to call) his arrow (see the second Perek of Bava Basra).