Language is a multifaceted and complex cognitive function
Imagine a situation where one is in a foreign country and cannot utter a word in the local tongue. Further, imagine that gesturing in that country would follow a peculiar logic of its own that one could not comprehend. Under such circumstances one quickly comes to realize the importance of being able to communicate with others, through speaking, gesturing, reading, and/or writing. Indeed, the seeming ease at which one normally commands one’s mother tongue is highly misleading. In reality, language is one of the most complex and amazing of human cognitive functions.
Difficulties in developing computer programs that would be able to command language well enough to carry a conversation with a human is one example of the complexity of the task that the brain faces when listening and speaking. Further, out of all species, mankind is the only one capable of the kind of highly sophisticated and abstract form of communication that language represents. To some extent it has been debated whether language is unique to humans (i.e., whether ”speech is special”) and there are language-like communicative calls and gesturing in other animals. The most striking manifestation of language ability in other species have been obtained in studies where sign language was taught to non-human primates (Gardner and Gardner, 1969), however, even the best of these examples fail to compare with the richness of human language.
Human language is a multifaceted skill. In order to communicate effectively, one has to know the meanings of different words (semantic knowledge) and have sufficient command of grammar to organize the words in an appropriate manner to be understood. Further, in order to read and write, one also has to have command of the orthographic (how words are written) and phonological (how words are pronounced) knowledge. With respect to this, there is variability between different languages, with prominent ambiguity in English (as there is no one-to-one correspondence between the written form and pronunciation) and non-ambiguous pronunciation in some other languages such as Italian and Finnish, where there is one-to-one correspondence between the written form and pronunciation.