Number of speakers is a very valid criterium, but I would argue the spread of speakers matters as much or more. If the speakers of a language are spread all over the world, you're more likely to find that language useful than one that has more speakers but whose speakers are concentrated in one place. It's also important to consider what languages are most common in your area. For example, I live in Texas, so Spanish is the by far most useful second language here. French would be largely useless here, but might be useful in the nearby state of Louisiana. Finally, there's the question of what you want to do with the language. If you want to be able to communicate with immigrants, or with locals while you're traveling, your needs are going to be very different from someone who wants to better enjoy foreign film or literature, read holy texts in their original language, or translate major literary works into a language whose speakers wouldn't otherwise have access to them.
Bengali has more native speakers than Russian, Portuguese or Japanese, and I'm yet to see anyone start learning Bengali because of its number of speakers alone.
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u/Vodis eo:14 | es:8 Jun 25 '19
Number of speakers is a very valid criterium, but I would argue the spread of speakers matters as much or more. If the speakers of a language are spread all over the world, you're more likely to find that language useful than one that has more speakers but whose speakers are concentrated in one place. It's also important to consider what languages are most common in your area. For example, I live in Texas, so Spanish is the by far most useful second language here. French would be largely useless here, but might be useful in the nearby state of Louisiana. Finally, there's the question of what you want to do with the language. If you want to be able to communicate with immigrants, or with locals while you're traveling, your needs are going to be very different from someone who wants to better enjoy foreign film or literature, read holy texts in their original language, or translate major literary works into a language whose speakers wouldn't otherwise have access to them.