This paper discusses the role of language planning in the maintenance of Welsh as a natural medium of communication by bilingual young adults in West Glamorgan and south-east Dyfed. It draws on findings from the Department of Adult Continuing Education project which examines attitudes towards, and the use of, the Welsh language by 16-18 year olds. ne study commenced in late 1991, and is an extensive survey of the linguistic backgrounds, attitudes and behaviours of respondents. This is now being followed by an ethnographic overview of Welsh-language youth culture in the region, and a qualitative investigation of the issues raised in the initial survey. Although relatively small, the geographical area of concern covers a wide variety of linguistic environments, ranging from populations of under 10% Welsh speakers, to those where over 80% are able to speak the language. This is therefore illustrative of the complexity necessary in the formulation of what is seen by many as an essential language planning strategy.