Is the word large scale hyphenated in English?

No, "large scale" is not hyphenated in English. It is generally written as two separate words.

However, there are some exceptions:

* When used as an adjective: "We are looking for a large-scale solution to the problem."

* For clarity: If you're using it in a specific context where it might be unclear, you could hyphenate it for clarity. For example, "They are conducting a large-scale study, not a small-scale one."

In most cases, though, "large scale" is written as two separate words.