A very high proportion of the four billion plus users of mobile phones come from countries where English is not the primary language. And yet, mobile operators in China and India (which have nearly a billion subscribers between them) have not reached even half their population.

In Africa too, mobile phone usage is growing at 50 to 60 percent per year. The Democratic Republic of Congo (population: 60 million) has 10,000 fixed phone lines but more than a million mobile phone subscribers. In Chad, the fifth least-developed country, mobile phone usage jumped from 10,000 to 20,000 in three years.

Mobile phone technology has helped many users bypass the need for a fixed-line phone, and is gradually shaping up as the main access point to the internet for the users. Unlike computer or television, a mobile device is not too power-hungry and be charged up easily even in areas that receive a couple of hours of power supply every day. And it is one device that people always carry with them - and reach out to check news.

Now for the challenges.

The BBC World Service publishes websites in 32 languages and has a global audience yet we need to employ a single technical architecture and interface that's suitable for all our sites. When editorial staff publish a page for the Desktop version of their respective websites, a mobile version is automatically generated on-the-fly. Behind the scenes, the in-house content management system employs a pre-defined set of rules to convert the multi-column layout into a single column, linear structure, more suited to a mobile environment. The benefit of this is that our busy editorial teams don't have to spend extra time and effort populating two versions of the same site.

The range of devices use when visiting our sites is wide and they vary considerably in terms of screen width, script support and multimedia capabilities. While some of our users are enjoying a near hi-web experience, surfing on the latest smartphone, many more are using low-spec devices, some with screens as narrow as a third of the width of an iPhone screen.

This means we need to keep markup and style simple, keep the layout as fluid as possible and try to maintain a balance between the need to scroll (for non-touchscreen users) and keeping links well-spaced apart (for touchscreen users).

Support for languages also varies greatly between devices. It depends very much on which script the language is written in. The basic Latin script is generally well-supported so we can be sure that what we publish in English, Spanish or Portuguese will be readable on nearly all devices.

The same cannot be assumed for content published using modified Latin (Vietnamese, Turkish) or non-Latin scripts (Cyrillic, Perso-Arabic, Devangari, Sinhala, Chinese, Burmese); many devices are unable to render the characters correctly and will instead present the reader with a screenful of boxes.

And then there's weight. Some of these scripts use double-byte characters which means that you have to download more kilobytes in order to read the same number of characters. This isn't a concern for users on a high-speed, fixed-cost contract but if you're using a lower-speed connection or pay-as-you-go then every kilobyte costs time and money. As many of our users are in this situation, a key concern is to keep the weight of each site as low as possible. One method that we've employed is pagination, allowing us to break a page down into smaller chunks which, individually, are quicker to download than the whole thing in one go.

So, where are we now? We are already publishing mobile sites in Spanish and Russian and later this month, we will be rolling out new sites in Arabic and Portuguese. Then we'll begin developing solutions for the more complex languages and a proposition for feature phones that cannot cope with or reflect the richness of a web offer.

What will these be? Keep watching this space...

Sheila Thomson is a Software Engineer at BBC World Service Future Media. This post was cowritten by Sheila and her colleagues Santosh Sinha and Amber Rose