Frustration with their inability to really employ the language even after years of learning is the number one reason students of South East Asian languages stop before they accomplish fluency. For the dedicated student of Thai or Vietnamese, a preponderance of sometimes overwhelming obstacles must be master before even a level of fluency can be attained.

Thai and Vietnamese are difficult to learn

For English speakers, Thai and Vietnamese are much harder to learn than European languages. The English language and civilization share common roots with the European languages and cultures. Vietnamese and Thai, however, have considerably different sentence structures and are based on radically different conceptual models and cultural presumption. For example, a simple statement in English or Thai could require a paragraph in the other language.
Learning Thousands of Characters overshadows Listening and Speaking.

As intimidating as the cultural and conceptual barriers are, the Thai and Vietnamese writing systems deliver utmost difficulty to erstwhile language students. The ability to distinguish, interpret and pronounce the unfamiliar characters - each individually challenging to learn and remember - is crucial for any measure of proficiency.

People from South East Asia spend years learning their own language. Traditional Asian education emphasizes the memorization of large numbers of seemingly unrelated facts. Their languages are no exception.

Learning Thai or Vietnamese takes a lot of time

After one year of study, an English speaking student of Spanish, Italian or French would be able to converse minimally in the language and read and write letters with the help of a dictionary. But even assuming diligence, a student of Thai or Vietnamese may not be equal to the task. An Asian language student may not be able to recognize a appropriate number of characters and may not yet be capable of using a dictionary.

However, learning South East Asian languages is worthwhile. Once the student has overcome the initial problems, he will be able to get insights into an otherwise strange culture.