You will be able to discover new horizons with your use of English
You will be able to communicate and discover more
English enables you to encounter a wider group of people and ideas
There is no really simple way of saying this. I think the key word is "discover" which implies adventure.
このことを簡単に言う方法はありません。キーワードは"discover"で、この言葉は”[冒険](https://eikaiwa.dmm.com/uknow/questions/51280/)する”ということを意味しています。
You will be able to discover new horizons with your use of English
英語を使うことでいままで知らなかったことを知ることができる
You will be able to communicate and discover more
コミュニケーションを取ることができ、より発見することができる
English enables you to encounter a wider group of people and ideas
英語を使うことでより幅広い人々や考え方に触れることができる
English can help me to learn new things I didnt know by talking to new people.
I can discover new things by learning English and meeting new people.
"English can help me to learn new things I didn't know by talking to new people." This explains that if you learn English you will be able to speak to new people and you can learn new things from them.
"I can discover new things by learning English and meeting new people." This is another way of explaining that you want to learn English so that you can learn new things from new people.
例文
"English can help me to learn new things I didn't know by talking to new people."
新しい人と英語で[話す](https://eikaiwa.dmm.com/uknow/questions/33800/)ことで知らなかったことを[知る](https://eikaiwa.dmm.com/uknow/questions/53056/)ことが出来る
英語を学べば、新しい人と話すことが出来、その人達から新しいことを学ぶことが出来ると説明しています。
例文
"I can discover new things by learning English and meeting new people."
英語を学び、新しい人と会うことで新しいことを学ぶことが出来る
新しい人から新しいことを学ぶことが出来るように英語を学びたいと説明する別の表現です。
If I learn English I can communicate better with people around the world
I can learn more things through communication with foreigners
When a person knows English it opens up a new world of discoveries. Many countries speak English or at least have a base of English knowledge. If you can communicate with foreigners and people from other countries it can widen your knowledge or it can "broaden your horizons". This is a typical English expression. "Traveling can broaden a person's horizons."
If you would like to explain in more detail you can say "If I am able to communicate in English, I will be able to learn many new things because I can talk with more people".
英語を話せると、世界が広がりますよね。多くの国々では英語を話し、最低でも 英語の基礎知識があります。英語で他国の人とコミュニケーションが取れたら、知識が広がります。英語では、そのことを”broaden your horizons”（視野を広げる）と言います。一般的な英語表現です。
例：Traveling can broaden a person's horizons.（旅は人の視野を広げる。）
もっと詳しく説明したいのであれば、”If I am able to communicate in English, I will be able to learn many new things because I can talk with more people."（英語でコミュニケーションを取ることが出来るようになれば、より多くの人と会話できるので、新しいことを沢山学べます。）
You will be able to learn things you did not know before
To study is to learn about something new or something you are not as good at so if you want to learn and be better at speaking in english then you would study it to become better
To learn is to be able to do new things that you could not before and the more you learn them the better you will get at them as well
Learning English will allow you to broaden your scope of knowledge.
"Learning English will allow you to broaden your scope of knowledge."
A simple sentence would be, "Learning English will help you to learn things you did not know."
Allow - To provide you with the opportunity to do something.
Broaden → To expand and increase your knowledge.
Scope → The extent of your understanding, knowledge, facts, etc.
Knowledge → The facts, information, details that you know about a subject, person, etc.
"Learning English will allow you to broaden your scope of knowledge."（英語を学ぶと知識が広がる）
シンプルに言うと、"Learning English will help you to learn things you did not know."（英語を学ぶと知識が広がる）。
Allow - ～をする機会を与える
Broaden → 知識を広げる／増やす
Scope →〔理解・知識・事実などの〕範囲
Knowledge →〔人・物事について〕知っている事実・情報・詳細
If you learn English, you can communicate with people of various backgrounds all over the world, thereby learn new things you did not know before.
If you learn English, you can acquire new knowledge by effectively interacting with people around the world.
If a person wants to acquire new knowledge, that is, things that he/she did not know before, he/she has to either study, or communicate / interact with other people. Lack of knowledge of a widely spoken language such as English can limit someone from widening his/her knowledge. Learning English increases a person's chances of being able to communicate confidently with people around the world and thereby get to know new things that he/she did know before.
So, you may say to someone:
If you learn English, you can communicate with people of various backgrounds all over the world, thereby learn new things you did not know before.
or
If you learn English, you can acquire new knowledge by effectively interacting with people around the world.
新しい知識を身につける（今まで知らなかったことを学ぶ）には、勉強するか、他の人と交流しなければ（コミュニケーションを取らなければ）なりません。
英語など広く話されている言語を知らないことは知識を広げる上で妨げになります。
英語を学ぶことで世界中の人と自信を持ってやり取りできるようになりますし、それによって知識も広げられます。
次のように言えます：
If you learn English, you can communicate with people of various backgrounds all over the world, thereby learn new things you did not know before.
（英語を学ぶことで世界中のさまざまなバックグラウンドの人とやり取りできるようになりますし、それによって知識も広がります）
If you learn English, you can acquire new knowledge by effectively interacting with people around the world.
（英語を学ぶことで、世界中の人とやり取りできるようになり、知識を広げられます）
You will be able to learn things you never could’ve imagined!
Learning English could open up a lot of opportunities!
Saying “you never could’ve imagined” means you could learn things that you never thought or dreamt of!
You can also say “open up a lot of opportunities”, meaning that when you learn English you will have many chances to do things, like new work things, travel, friendships etc.
Ex: You will be able to learn things you never could’ve imagined!
“you never could’ve imagined” と言うと「想像もできないようなことが学べる」という意味になります。
“open up a lot of opportunities” という言い方もできます。「英語を学ぶと〔仕事・旅行・友情などに関して〕チャンスが広がる」という意味になります。
例：
You will be able to learn things you never could’ve imagined!
（想像もできないようなことが学べる）
イギリス 
南アフリカ 
アメリカ合衆国 
