Sign language or bahasa isyarat is a different kind of language.
In wikipedia:
Indonesian Police Initiative
In a recent announcement, the Indonesian National Police spokesman Insp. Gen Argo Yuwono said that the Indonesian police will provide sign language interpreters during police conferences to assist the disable and bridge the communication barriers.

In the US, the famous NYC sign language has been in the news quite often.
For more reference on sign language interpreter please go to these links:
The Inasli Jakarta Website

The WASLI website

The Federal Association of Interpreters and Translators (Bundesverband der Dolmetscher und Übersetzer e.V., BDÜ) profile. Their website is below (click on the photo to go to the website)
