In the UK, where patterns of consumption are close to the European average, mobile voice usage should overtake fixed voice in the second quarter of 2008.
This has already happened in France, where mobile voice calls keep growing despite the widespread availability of practically free voice over broadband.
However, mobile voice is not expected to overtake fixed voice in the Italian market until the first quarter of 2009, and for about two years in the German market, the largest in western Europe.
"Developed countries tend to have very stable demand for voice," said Andrew Parkin-White, principal analyst at Analysys Research.
"The volume varies quite significantly between individual countries, but northern Europeans are generally the most talkative."
Portugal, which has the lowest voice consumption in western Europe, was the first country in which mobile overtook fixed calls, while Sweden, which has one of the highest, will be among the last to change.
"Consumers have relatively constant budgets for voice, so fixed voice volumes basically reflect the 'unaffordability' of mobile voice," said Rupert Wood, principal analyst at Analysys Research.
"The trick for mobile operators has been to translate stable demand into an affordable proposition. Once mobile can meet demand affordably, any kind of competitive pricing for voice on fixed or broadband is largely irrelevant."