There are been a lot of articles about the best way to warm up your vocal instrument. Some protocols involve a series of lip movements, tongue stretches, etc. that are performed without vocalization. Often, these are often followed up by a selection of one’s favorite tongue twisters. What we do often depends on our personal preference.
I was thinking about the parallel between vocal warm-ups used by voice actors and the “non-speech oral motor exercises” used by Speech/Language Pathologists to change speech sound production. Non-speech oral motor exercises (NS-OME) were defined by Lof and Watson in 2004 as “any technique that does not require a person to produce a speech sound but is used to influence the development of speaking abilities”. In a survey conducted by Greg Lof, which was presented at the 2006 American Speech Language Hearing Association Convention, 85 % of speech pathologists surveyed were using non-speech oral motor exercises to change speech production. Lof reported on ten research studies which evaluated the effectiveness of NS-OME on speech production. Nine of the ten studies showed no benefits; the one study that showed benefits had serious methodological flaws.
The bottom line is that when you are warming up, if you want to improve your diction, focus on tasks such as tongue twisters which require the integration of the breath control, vocalization and speech production to maximize your efforts. Don’t waste your time stretching your tongue, puckering and smiling with your lips or performing other non-speech oral motor exercises.