Children as young as seven months can understand and learn grammatical rules (a). Furthermore, studies of 36 documented cases of children raised without human contact (feral children) show that language is learned only from other humans; humans do not automatically speak. So, the first humans must have been endowed with a language ability. There is no evidence language evolved (b).
Nonhumans communicate, but not with language. True language requires both vocabulary and grammar. With great effort, human trainers have taught some chimpanzees and gorillas to recognize a few hundred spoken words, to point to up to 200 symbols, and to make limited hand signs. These impressive feats are sometimes exaggerated by editing the animals’ successes on film (Some early demonstrations were flawed by the trainer’s hidden promptings (c)).
Wild apes have not shown these vocabulary skills, and trained apes do not pass their vocabulary on to others. When a trained animal dies, so does the trainer’s investment. Also, trained apes have essentially no grammatical ability. Only with grammar can a few words express many ideas. No known evidence shows that language exists or evolves in nonhumans, but all known human groups have language (d).
Furthermore, only humans have different modes of language: speaking/hearing, writing/reading, signing, touch (as with Braille), and tapping (as with Morse code or tap-codes used by prisoners). When one mode is prevented, as with the loss of hearing, others can be used (e).
a. G. F. Marcus et al., “Rule Learning by Seven-Month-Old Infants,” Science, Vol. 283, 1 January 1999, pp. 77–80.
b. Arthur Custance, Genesis and Early Man (Grand Rapids: Zondervan Publishing House, 1975), pp. 250–271.
“Nobody knows how [language] began. There doesn’t seem to be anything like syntax in non-human animals and it is hard to imagine evolutionary forerunners of it.” Richard Dawkins, Unweaving the Rainbow (Boston: Houghton Mifflin Co., 1998), p. 294.
c. “Projects devoted to teaching chimpanzees and gorillas to use language have shown that these apes can learn vocabularies of visual symbols. There is no evidence, however, that apes can combine such symbols in order to create new meanings. The function of the symbols of an ape’s vocabulary appears to be not so much to identify things or to convey information as it is to satisfy a demand that it use that symbol in order to obtain some reward.” H. S. Terrance et al., “Can an Ape Create a Sentence?” Science, Vol. 206, 23 November 1979, p. 900.
“...human language appears to be a unique phenomenon, without significant analogue in the animal world.” Noam Chomsky, Language and Mind (Chicago: Harcourt, Brace & World, Inc., 1968), p. 59.
d. “No languageless community has ever been found.” Jean Aitchison, The Atlas of Languages (New York: Facts on File, Inc., 1996), p. 10.
“There is no reason to suppose that the ‘gaps’ [in language development between apes and man] are bridgeable.” Chomsky, p. 60.
e. “...[concerning imitation, not language] only humans can lose one modality (e.g., hearing) and make up for this deficit by communicating with complete competence in a different modality (i.e., signing).” Marc D. Hauser et al., “The Faculty of Language: What Is It, Who Has It, and How Did It Evolve?” Science, Vol. 298, 22 November 2002, p. 1575.
[From “In the Beginning” by Walt Brown
]In the Beginning: Compelling Evidence for Creation and the Flood - 13.   Language