There seem to be fashions in which languages people choose to learn and in which languages are in demand by employers. Some languages, notably French, German and Spanish, are perennial favorites, at least in English-speaking countries. Other languages may enjoy popularity for a while, then are displaced by different ones. In the UK there are increasing numbers of people learning Chinese and Japanese, and Spanish is also gaining more followers, particularly among adult learners. In the USA there is currently a significant demand for people with Arabic language skills.
During the Cold War, many of the inhabitants of Eastern European had to learn Russian at school, a language few of them felt much affection for. Since the collapse of the USSR, other languages have become popular, particuarly English and German. And according to Radio Polonia, Russian has been making a come back in Poland recently.
Which languages are popular in your country?