Whatever language you learn, the exercise is good for the brain. Some languages are more difficult than others. For example, an English speaker will need an average of 22,000 hours, or 88 weeks, to master
Japanese.
Chinese,
Arabic and
Korean take about as much time.
It is true that Japanese and Chinese require you to memorize thousands of characters. You will need excellent visual memory to commit these thousands of characters to memory.
The
Arabic, in turn, uses fewer vowels and only very few words similar to those of European languages. While the Korean alphabet Hangul is known as one of the most logical writing systems in the world, sentence structure and syntax are particularly complex.
Turkish and
Hebrew "only" require 44 weeks of study for an English speaker. The easiest languages to learn are those closest to your native language. If, for example, you are French, then
Spanish
or
Italian will be easier for you to learn than, say, English or Swedish.
If you are German, then English or Swedish will be easier. To develop competence in these languages, it will only require 600 hours, or 20 weeks, of study.