I recently saw a survey that asked Japanese people what language they wanted to study (after they learned to speak good English if they hadn't already) and the most popular languages were French, Chinese, Korean, German, Spanish and Italian (not necessarily in this order.) And then some people were interested in learning Russian, Thai, Portuguese and Arabic. I personally think all the thousands of languages are equally beautiful, but these ten alone appear to make up more than 95% of the language teaching market in Japan.

Hola, estoy estudiando tu idioma, el castellano durante muchos años pero sé hablar muy poco. Una cosita, en este caso sería más natural decir 日本の人たちは英語を除いて何語を勉強していますか？