<P> These properties of ASL allow it a variety of word orders, leading many to question which is the true, underlying, "basic" order . There are several other proposals that attempt to account for the flexibility of word order in ASL . One proposal is that languages like ASL are best described with a topic--comment structure, where words are ordered by their importance in the sentence rather than by their syntactic properties . Another hypothesis is that ASL exhibits free word order, in which syntax is not encoded in word order whatsoever, but can be encoded by other means (e.g. head nods, eyebrow movement, body position). </P> <P> A common misconception is that signs are iconically self - explanatory, that they are a transparent imitation of what they mean, or even that they are pantomime . In fact, many signs bear no resemblance to their referent, either because they were originally arbitrary symbols or because their iconicity has been obscured over time . Even so, in ASL iconicity plays a significant role; a high percentage of signs resemble their referents in some way . This may be due to the fact that the medium of sign--three - dimensional space--naturally allows more iconicity than oral language . </P> <P> In the era of the influential linguist Ferdinand de Saussure, it was assumed that the mapping between form and meaning in language must be completely arbitrary . Although onomatopoeia is a clear exception, since words like' choo - choo' bear clear resemblance to the sounds that they mimic, the Saussurean approach was to treat these as marginal exceptions . ASL, with its significant inventory of iconic signs, directly challenges this theory . </P> <P> Research on acquisition of pronouns in ASL has shown that children do not always take advantage of the iconic properties of signs when interpreting their meaning . It has been found that when children acquire the pronoun "you", the iconicity of the point (at the child) is often confused, being treated more like a name . This is a similar finding to research in oral languages on pronoun acquisition . It has also been found that iconicity of signs does not affect immediate memory and recall; less iconic signs are remembered just as well as highly iconic signs . </P>

When was asl recognized as an official language