Psychology

The inability of infants to communicate verbally makes it hard for parents to understand them.  Most of the time, a parent is left to guess the reason as to why a baby cries.  This is why the development of infant sign language is helpful because non-verbal cues may help parents understand what their child is trying to say.

The study of baby sign language is not new it has been studied since the 1980s.  Significant researches show that babies do possess the ability to learn sign language, especially if assisted by the parents.  In one research, it has been found that infants use sign language because they can understand gestures more than they understand sounds in their early stage of life (Acredolo and Goodwyn, 1988).  The same applies to their parents, who understood the actions of their babies better as compared to the sounds they were making.  Acredolo and Goodwyn (1988) also stated that sign language development is not the same for all infants.  The level and speed of learning new sign languages may vary according to the gender, order of birth, and manner of acquisition of the sign languages of the babies.

Based on these findings, it may be considered that infant sign language is still yet to be explored.  It would be wrong to generalize that most babies can be capable of communication through sign language.  Teaching a baby how to use gestures to communicate is like teaching a baby how to swimit is possible, but only in a few cases.  The idea of teaching sign language to infants is still questionable to other parents.  Although Acredolo and Goodwyn (1988) mentioned that symbolic gesturing may help in verbal language development, some parents still think that teaching a baby sign language may hinder or slow the ability of babies to speak real words.  Considering this case, it is recommended that another research that shows conclusively the correlation of symbolic gesturing with verbal language development be done.

It would be also advisable to see if infant sign language is applicable to babies from different locations.  It is possible that only babies from industrialized countries have been studied for this specific research.  What about the babies in other countries, especially those living in the Third World  This type of research may show if the environment affects the ability of babies to learn sign language.

Methodology
In the case study done by Acredolo and Goodwyn in 1985, the subject Kate, the first-born female baby of professional parents was studied from the time of her first word in her ninth month up to her second birthday.  Weekly reports of her progress were made and her verbal words accompanied by gestures were especially noted.

The second case study of Acredolo and Goodwyn done in 1988 were composed of two methodologies.  The first methodology, called the Interview Study, involved 38 16-18 month old babies.  The mothers of these babies were interviewed about the verbal and non-verbal behaviors of their infants.  The second methodology was called the Longitudinal Study and it involved 16 11 month old babies.  The mothers of the babies were tasked to keep weekly records of their babys verbal and non-verbal behavior for nine months up to the babys 20th month.  Diary recordings were studied for 11-20 months.  At 17 months, the gestural imitation of the infants was studied.  The parents of the infants were interviewed and were tasked to assess the language development of their babies at 20 months.  Finally, at the 24th month, a follow-up was done by visiting the houses of the subjects and personally observing their development.

For the first case study, it has been found that oftentimes babies learn new sign languages because of the teaching of their parents, and sometimes by learning to devise signs by themselves (Acredolo and Goodwyn, 1985).  Acredolo and Goodwyn (1985) mentioned that babies make two types of gestures the iconic and the indexic gestures.  Iconic gestures are signs made that resemble the characteristics of objects.  An example of this is by cupping the hands when describing a ball.  Indexic gestures, on the other hand, are gestures that symbolize actions that are associated with objects.  For example, a baby may mimic the sniffing action when describing a flower.  Acredolo and Goodwyn (1985) also stated in their research that it is not clear whether the subject does these sign languages because she fully understands the connection of objects with one another.

In the second case study, the Interview Study showed that the sex and the number of the siblings of the infant have no significant effects on their sign language learning.  This methodology also mentioned that it is the infant that chooses what gesture to use.  In the Longitudinal Study, however, it was shown that sex and birth order do have significant effects on the sign language learning of a child.  The results also showed learning can be based on the interaction of the parents and the child.  And finally, the Longitudinal Study provided evidence that symbolic gestures support the childs verbal language vocabulary.

Results and Discussion
The results of the second research done by Acredolo and Goodwyn in 1988 supported the research done in 1985 that sign language is indeed possible in babies.  However, there was only one subject studied in 1985, whereas the sample size significantly grew in 1988.  The increase in the number of subjects may help provide information about the other factors that may contribute to the sign language learning of infants like sex, birth order, and interaction with the parents or siblings.  This methodology is better than the methodology used in 1985 wherein only weekly records and observations of a single subject were studied.