Why isn't French practical?
It might depend on whether or not you have interests in a particular world region?
French is one of the official UN languages. It also is useful for Western Europe and large parts of Africa, including certain areas of North Africa. It is useful for parts of the Caribbean, South Pacific, and SE Asia. French also may be useful for scholarly literature published in that language, including research on France's former colonial areas.
Spanish is primarily useful for Latin America and Spain. Arabic is useful for much of the Middle East, though not so useful in certain Islamic countries, e.g., Iran, Turkey, Pakistan, Indonesia, and certain parts of sub-Saharan Africa with Muslim populations. Chinese is useful for China, Taiwan, Singapore, and the Chinese diaspora in SE Asia.
Since you've already studied French, you could continue it and start one of the other languages, any one of which could be usefully combined with your French studies. You could take coursework in languages without declaing a formal minor. The Twelve Most Useful Second Languages for English Speakers - a knol by Dominic Ambrose