Grammar 
Verb - Infinitive (auxillary verb + bare infinitive)
日本語で --> 助動詞 + 原形不定詞 (じょどうし + げんけいふていし)
NOTE: First of all, before you freak out, don't worry about all the technical jargon in the above title; it will be explained in laymen's terms, hopefully. Also, take anything you know about English grammar and throw it in the trash because the above grammar point doesn't have a technical name in English...at least that I have found. This grammar point falls under the 'infinitive family'. Usually all forms of the infinitive are studied together when studying English as a primary language. Japan's English textbooks split the infinitives into each of their three levels of JHS textbooks. They are guilty of split infinitives! LOL...okay, I'll stop!
Definition: This particular grammar point focuses on sentences that contain an (auxillary verb + a bare infinitive) in the same sentence. Now, before you freak out:
An
auxillary verb is the exact same as a helping verb
(will, shall, may, might, can, could, must, should, would, need). These helping verbs are found right before the main verb in a sentence. Look at the examples below for clarification.
A
bare infinitive is an infinitive (to + verb) without '
to'. When an auxillary verb and an infinitive are used in conjunction with each other, English grammar dictates the infinitive changes to the bare infinitive form. If you're still confused, just look at the examples below to hopefully bring some clarity.
Examples: You must help your mother. We must do something. I must get there by two o'clock.
av bi av bi av bi
Fun Fact: "Do shinkansen trains run on the left or right-hand side of the track?" (answer below)