Otherwise: Is it necessary to use it in this sentence?

[MaverickCrystal]

In Plain English tutorials, you will hear lots of new words, words you might not otherwise hear in English.

is this equivalent to:

In Plain English tutorials, you will hear lots of new words, words you might not hear in English.

If they have equal meanings. Why is it necessary to have "otherwise" in the original sentence?
Please kindly explain in detail so that I can fully understand the reason behind this concept.
Thank you

 

[emsr2d2]

In Plain English tutorials, you will hear lots of new words, words you might not otherwise hear in English.

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