Language learning and acquisition is an excellent potential thesis topic for students working towards a master's degree in English, Linguistics, Education or English as a Second Language (ESL). It is also a good choice for seniors who have opted for the thesis option, especially those in honors programs. Specific topic choices are plentiful, ranging from general areas like developmental language acquisition in children to demographic studies of international students in college.
One of the best areas of specialization to begin looking for topics for the thesis is has to do with theories on how children learn language. Most research in this area will fit well into the one or two semester model of thesis research and writing. Students will find a fascinating array of possibilities, like best practices for language facilitation among prekindergarten children, or the role of music in the developmental stages of speech and language training. The latter topic could even lend itself to studies of children with autism disorders. You could also concentrate on a specific demographic, such as fifth-grade English language learners.
Another excellent possibility for thesis topics would be to concentrate your research in a technology-related area. For example, you could examine the relationship between computer-assisted language learning and success among two different study groups, such as boys and girls. Other good topics would include the use of web technologies for language interaction or the use of smart phone apps in language learning: Demographic groups that would offer interesting studies along these lines would include Japanese students in American colleges, children of multilingual families or Latino students who spend a good deal of time using social networking.
The trials, tribulations and successes of second language learners also make for interesting theses. Along these lines, you could investigate the effects of reflective journal writing on a particular student population, such as Romanian or Japanese students. You would likely also find fascinating the possibility of topics such as vocabulary learning strategies for speakers of English who are trying to learn Chinese, possibly comparing the success rates of those who do so in the United States versus in China. Another engaging topic would be the perceptions of ESL teachers who work with adolescent learners with specific learning disabilities.
Finally, you could simply choose to write on a specialized topic for your thesis, provided you get the approval of your thesis director. You could investigate motivational teaching strategies for foreign language learning by teens or the use of multimedia to help Thai and Filipino college students learn independently. You could even decide to examine the efficacy of a specific learning theory, such as Mezirow's Transformative Learning Theory, which involves critical thinking and goes beyond knowledge acquisition, using active engagement and questioning.