When all goes well, the mastery of a second language can be beneficial and highly gratifying to a student. A new language affords an intimate view of another culture and a great new way to communicate. Students who are adept with foreign language are likely to acquire a more worldly view. In a world in which globalization is becoming increasingly essential, fluency in more than one language can be a powerful career asset. At the same time, a second language goes far in enriching and fortifying students' understanding of their native language and how it works. Foreign language mastery is intellectually challenging and is thought by some to be the mark of a truly cultivated mind.

To become adept with a foreign language a student has to make use of multiple neurodevelopmental functions that enable him or her to understand the second language while listening and reading and to make use of that foreign code for speaking and writing. Some of the key functions are listed below:

Phonological awareness - having a good "ear" for language. This involves the ability to process the sounds within a word clearly and distinctively and with sufficient speed to keep pace with the flow of incoming verbal messages.
Semantics - understanding in depth the true meanings and shades of meanings of words. Foreign language learners must be competent at acquiring new vocabulary with ease and with true comprehension.
Grammatical Construction - knowing how to form and interpret sentences. A student must master the grammar of a new language and develop knowledge on how the order of words will impact on meaning.
Overall Oral Language Fluency - being able to express ideas without too much effort and with reasonable sophistication. Facility at translating thoughts into language is a challenge for all students. Doing so in a second language (without having to "dumb down" your thinking) is a particularly notable feat.
Rule Understanding and Application - absorbing a language's system of rules that regulate punctuation, capitalization, and spelling. A student must know when and how to apply the rules.
Cumulative Memory - retaining over time all of the above aspects of language. Foreign language is highly cumulative; you must remember in March the vocabulary and conjugations you learned in November!
Speed of Processing - keeping pace with the demands. Students must be able to keep up with the rapid onslaught of new words and rules; otherwise they rapidly fall behind and feel overwhelmed, anxious, and discouraged.
Rapid Retrieval and Pattern Recognition Memory - having quick access to what you have learned. Students must find or recognize words they've seen or heard before and remember sentence construction while speaking or writing or reading or, of course, taking a quiz in the new language.
Active Working Memory - holding things together in your mind. In a foreign language you have to be able to think up ideas and find the right words at the same time - without forgetting the ideas.
Foreign Language Intuition or Affinity - having an inner sense of how a language is structured. Some individuals are just natural foreign language learners. They have a knack and possibly as well a high level of motivation for language learning and they may overcome many obstacles as they become readily proficient in a foreign tongue.
Foreign language learning is also a risk-taking venture for most students. Those who are very self-conscious or anxious may fear humiliation when they try to speak in the new language. Significant performance anxiety is an especially common barrier to second language achievement.

There are some students who find foreign language learning downright frustrating and unrewarding. They may confront unacceptable grades in a Spanish, French, or Latin class or else find themselves exerting so much time and effort in such courses that they start to lose ground in other subjects. Foreign language impairments can stem from any one or several deficits in the neurodevelopmental functions listed above. In general, if a student has a problem with verbal learning or memory in his first language, he or she is at risk for failure in incorporating a second language. So it is that learners who have had a hard time acquiring reading decoding skills in English are likely to falter when faced with a second sound system. In fact, if a student has not totally internalized the sounds of his own language, attempts to assimilate another range of phonemes can be fruitless. Those who have always found it hard to master new vocabulary in their first language may have their problem amplified when they try to access words within a whole new lexicon. Problems such as these are often encountered in persons for whom English is a second language; they may develop learning difficulties in English because they never sufficiently mastered their native language.

Students should probably postpone the study of a foreign language until they are reading and writing at or very near grade level in their first language. Likewise, those who have chronic difficulties meeting the memory demands of school should not be encouraged to study a second language at an early age. For others it matters very little when they take on a foreign language. Some students with serious learning impairments may require a foreign language waiver, and colleges should be willing to admit such individuals. All students should at least attempt the learning of a second language at some point in their education with the understanding that the requirement can be waived when and if such attempts are obviously not working. For some, foreign language teaching may need to be undertaken at a slow pace and with a stress on oral conversation rather than a heavy dose of reading and writing. Considerable individualized support may be a necessity for students with the kinds of differences in learning we have described. So many adults look back on their educational years and regret not having mastered a second (or third) language. Hopefully as many students as possible can reap the benefits of this highly practical and enriching component of education, but we must acknowledge that there exist some individuals who simply are not wired for this kind of learning.