一年は四月に始まるって英語でなんて言うの？

When something begins from is also called to 'start from' so you could say 'the school year starts from April' although 'the school year starts in April' these would both explain the same thing

Talking about the school year, we would say, "The new school year starts in April." New - something that has not been done before. (This is a brand new school year!) Start - to begin something. (The race starts in 5 minutes.) To talk about the new work year or the fiscal year, we would say"The new work year begins in April." fiscal year - the year as divided or arranged for accounting and tax purposes. (The fiscal year begins in April.) Begin - to start (You may begin the test now.)

When talking about the school/work year in Japan, you want to explain that it starts in April. The above example statements may fit this scenario.

"In Japan, the school year starts in April" clearly tells us who the subject is (school students) and what is happening (they go back to school) and when (April). "Students go back to school in April" is an abbreviated version of the above example sentence. It also relies on the readers/listeners knowledge (perhaps from context) to know that we are referring to a new school year. A common phrase used in media/marketing for this time of the year is "Back to School". Sales use this tagline to promote this time of the year and prepare for the student's return after a long break. "We all go back to work in April and are ready for the new year ahead" shows a little more detail when describing a work year, or even fiscal year, for employees and when this new cycle takes place (April).

Any of the above would be a simple way of talking about when the school/work year starts.

To explain that school opens in April for the start of the year you can use the sentences above. Schools start at different points in the year all over the world as well as holidays. In South Africa, the school year begins in January. "School opens in the next few weeks, that's in April." "In Japan school starts in April whereas in South Africa it starts in January."

"The start of the academic year is in Aprll." 'Academic year' is an alternative way of saying 'school year, and can also refer to other academic settings, such as a university. "The Japanese school year starts in April." In this example 'begin' is being used as a verb, as opposed to its form as a noun, which is 'beginning'.