Answer to Question 1
Writing, and arithmetic overlap and build on the same functions of the brain, it is not surprising that a child or adult can have more than one form of SLD (Scanlon, 2013). Recall that phonological awareness facilitates the ability to speak and, later on, to read and write. A single gap in the brain's functioning can disrupt many types of cognitive activity. These disruptions, in turn, can interfere with the development of important fundamental skills and compound the learning difficulties in a short time.
Answer to Question 2
A perceptual map forms that represents similarities among sounds and helps the infant learn to discriminate among different phonemes. These maps form quickly; 6-month-old children of English-speaking parents already have auditory maps different from infants in nonEnglish-speaking homes, as measured by neuron activity in response to different sounds (Kuhl et al., 2006). By their first birthday, the maps are complete, and infants are less able to discriminate sounds that are not important in their own language.