Because it's more interesting to travel when you know how to speak English.
It's more fun to travel when you know how to speak English.
It makes travelling more fun.
It makes travelling more fun. - this is a pretty basic way of saying it.
When answering a 'why' question, it is good to answer by starting with "because..."and if you want to be vague (not go into detail) then you could just say "it makes travelling more fun" but if you want to be a little more detailed then you could say "it's more interesting (or fun) to travel when you know how to speak English.
It makes travelling more fun.（旅行をするのが楽しくなります）
これはシンプルな言い方です。
'why' の質問に答えるときには "because..." で始めた方がいいです。
もし曖昧に答えたいなら、単に "it makes travelling more fun" と言えます。
もっと具体的に答えるなら、"it's more interesting (or fun) to travel when you know how to speak English."（英語が話せた方が旅行が楽しくなります）と言えます。
"I enjoy meeting new people during my travels and knowing English helps with that."
"Knowing English while abroad makes travelling more fun!"
"It makes travelling more enjoyable" is a very easy way to explain why you enjoy learning English.
"Knowing English while abroad makes travelling more fun!" once again tells the reader/listener what you like about learning/knowing English.
"I enjoy meeting new people during my travels and knowing English helps with that." This example sentence is similar to the ones above however it provides more detail. Not only does it tell us why you enjoy learning English but also how you apply it during your travels.
"It makes travelling more enjoyable"
（旅行するのがもっと楽しくなる。）
これはどうして英語を勉強しているのかを説明するとても簡単なフレーズです。
"Knowing English while abroad makes travelling more fun!"
（外国で英語を知っていると旅行がもっと楽しくなるよ！）
これも、相手にどうして英語を勉強しているのかを伝えるフレーズです。
"I enjoy meeting new people during my travels and knowing English helps with that."
（旅行中に新しい人たちに会うのが好きで、英語が役に立つんだ。）
この例は、上の例と似ていますが、もっと詳しく説明しています。どうして英語を学ぶのが好きかだけでなく、旅行中にどうやって英語をいかすことができるのかを説明しています。
Traveling will be even more enjoyable if I can understand English.
Being able to speak English makes traveling more fun.
If someone asks you why you study English, and you want to explain that it makes traveling more fun, you can say:
"Traveling will be even more enjoyable if I can understand English."
"Being able to speak English makes traveling more fun."
なぜ英語を勉強するか聞かれて、「英語が分かった方が旅行が楽しいから」と答えたいなら、次のように言えます。
"Traveling will be even more enjoyable if I can understand English."（英語が分かった方が旅行が楽しい）
"Being able to speak English makes traveling more fun."（英語が話せた方が旅行が楽しい）
I study English as travelling seems more fun if you can speak it
When asked why you study English, you want to say that you study English because it will make travelling more fun.Either of the above examples would be good.
日本 
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オーストラリア 
南アフリカ 
