Our recordings are providing rich data. Sample observations regarding phonological processes¹ are:

Substitution, e.g.,

• trill /r/ replaced by glide [j], as in [ʔazjag] for target /ʔazrag/ ‘blue’ (Qatari boy, age 3 years, 1 month) 
• sibilant /s/ replaced by interdental [θ], as in [ʔaθad] for target /ʔasad/ ‘lion’ (Qatari boy, age 3 years, 1 month)
• approximant /ʕ/ replaced by glottal stop [ʔ], as in [ʔanɛm] for target /ʕɛnab/ ‘grapes’ (Qatari girl, age 2 years, 2 months)

Assimilation, e.g., /b/ assimilating in nasality to /n/ in [ʔanɛm] for target /ʕɛnab/ ‘grapes’ (Qatari girl, age 2 years, 2 months)

Consonant cluster simplification, e.g., deletion of /l/ in [kʲab] for target /kalb/ ‘dog’ (Qatari boy, age 2 years, 8 months)

Similar processes are observed also in other languages.²

¹A phonological process is “...a mental operation that applies in speech to substitute for a class of sounds or sound sequences presenting a common difficulty to the speech capacity of the individual, an alternative class identical but lacking the difficult property (p.1 in D. Stampe, 1979, Stampe, D. (1979). A Dissertation on Natural Phonology. New York: Garland.).    
²See, for example, Z. Hua & B. Dodd (eds.), 2006, Phonological Development and Disorders in Children: A Multilingual Perspective. Clevedon: Multilingual Matters.

Our fieldworkers have begun gathering data. The audio recording uses wireless mics with signals saved as .wav files to an Edirol-09. A Qatari and a Palestinian child show the equipment, below.