During PhD and a junior faculty position at Monash (1975-1981) and then later at UNSW (1981-1999), Professor Denis Burnham researched infant perceptual development. He rode the exciting new wave of infant visual perception research in the 1970s and then was one of the first Australian punks in the 1980s to jump onto the equally, if not more, exciting newer wave of infant speech perception. From the mid-80s and throughout the 90s he embraced cross-disciplinary research, working with experimental phoneticians and speech scientists, and in the late 80s he added the use non-English languages (Thai and then many others) as an tool in order to probe speech perception development not only over ontogeny but also as a product of the mini-laboratories (called languages) so conveniently set up to allow natural manipulation of perceptual input.
After his appointment as inaugural Director of MARCS Institute at Western Sydney University in 1999, his research focus on experiential and inherited influences in speech and language development continued to develop in infant speech perception; auditory-visual (AV) speech perception; special speech registers, including , infant, pet, foreigner, computer, and lover directed speech; captions for the hearing impaired; tone languages, lexical tone perception, tone perception with cochlear implants, and speech-music interactions; human-machine interaction; speech corpus studies; and the role of infants' perceptual experience and expertise, in literacy development.
So too have his collaborations developed with phoneticians, linguists, engineers, clinicians, computer scientists, music cognition researchers, creative artists, and neuroscientists, with the result of many emergent issues, paradigms, results, and friendships.