Language is the most prominent way of communicating each other. Different cultures use different languages. The language that parents inherit you is the mother tongue. Accept that all other languages become the foreign language. In Sri lanka Sinhala is the mother tongue, English has become the most needed foreign language.
Some experts believe that primary school is the best place to begin learning a foreign language rather than secondary school. I believe it has both good as well as bad aspects
Learning a language is not like learning some other subjects. The more we practice a language, the more we get better. Since the mind of a primary child is fresh, it is easier for them to learn new words and enrich their vocabulary. It is not something child leans because they have to. They will also learn how to pronounce those words properly. Children in young age are not shy as teenagers. They say things out loud even though they don't know the meaning of it. These children benefit the slow and longer version of learning a foreign language, which adults will never have.
On the other hand this may leads some problems too. Mother tongue is the first language we learn. It is more important for the thinking process. It has to be rooted well for the better development of the brain. By trying to include another language in early age, children may get confused. Child might not be able to draw a line between his mother tongue, and the foreign language. By not distinguishing the different between those languages could leads the child to not to learn both languages properly. In secondary School there mother tongue is strong, that they know if there are learning another language.
In a different scenario if child lean the foreign language better than the mother tongue, mother tongue can become extinct, this is a main problem in Sri Lanka nowadays. Sri Lanka is the only country which speaks "Sinhala". But the necessity has given the "English" language the more concern.
Therefore in conclusion I believe learning a foreign language; in primary age has benefits as an individual, but as a nation it might have bad effects to the culture.