If you mean "Is learning English a good preparation for learning other languages", then my answer is both 'no' and 'yes'
No: For somebody who does not know any European Indo-European language, but wants to learn one, then it is better to start with the one they want to learn. There is no point in learning English first if they really want to learn French.
Yes: If speakers of a language other than a European Indo-European language already know one European Indo-European language (including English), then they may find learning a second one easier.
European Indo-European languages include all European languages except Basque, Finnish, Estonian, Hungarian and Maltese.
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