While mobile voice volumes have increased by 4% there between 2012 and 2014, most smartphone owners' patterns of use have "become more data-centric," the report says.
The research firm accounts for those voice volume increases with population gains, adoption of unlimited voice plans, more allowances, and a shift from landlines.
Three years ago, smartphone users made at least one call per week. Today, "twenty-five percent of smartphone users have become data-exclusive in a given week."
While some users are increasing their use of voice, "at the other end of the scale a growing proportion are not using voice at all."
Deloitte UK's survey, Mobile Consumer 2015, was based on a nationally representative sample of 4,000 UK consumers aged between 18 and 75. Fieldwork took place between May and June 2015.
This reduction in voice usage ties in with the more widespread use of data communications. In other words, social networks, instant messaging, and email.
Classic texting is also to blame, although it's declining too, the report indicates.
By 2018, almost 50% of smartphone owners won't make standard phone calls weekly, the report says.
But it's social networks, which that enhance communications through the sharing of more in-depth media like images, that are "usurping" private conversations.
Data benefits abound. One is that with non-traditional communications such as social networks and instant messaging, the user can choose when to respond.
"Voice conversation obliges a real-time response." The authors think that can be onerous.
Apps are also contributing to the slowdown in voice calling for some.
Apps can "replace the calls we would have previously made" to order take-out, request a taxi, make an appointment, or conduct banking, the report says.
As one might expect, it's the younger generation that has most wholeheartedly adopted data-exclusive smartphone communications. The report found that 29% of the U.K. 18 to 24 year olds weren't making calls. The average for adults was 25%.
The authors think that this youth-slant will become even more prevalent as "teens and pre-teens are being weaned on messaging."
Kids are often given non-cellular, Wi-Fi-only devices without voice functions, and so get used to the idea of textual, non-voice electronic communications early.
The authors go on to say that they think voice is unlikely to disappear altogether, though. They think that spoken conversations will "migrate to apps and new forms of operator-managed voice services."
Voice-over-Wi-Fi and Voice-over-LTE (VoLTE) are two technologies that could enhance voice calls. I wrote about VoLTE recently in "Voice over LTE gaining momentum globally."
"Users will upgrade voice calls to video whenever images rather than words provide a faster, or richer description," the report says.
Communicating a parts description by a remote service engineer to an office, say, can often be accomplished successfully by a captured image along with a voice call, and is an example of that combination.
Both talking and being online will help in "little, but important ways, for example guiding someone to their destination while looking at a map," the report says.
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