This chapter explores the impact of language confidence levels on teachers’ ability and willingness to deliver aspects of the school curriculum through a minority language – in this case, Welsh. Wales boasts a highly successful bilingual and Welsh-medium education system that implements a variety of teaching strategies to develop pupils’ Welsh and English skills (Welsh Government, 2010). At the same time, the introduction of Welsh to L2 pupils in English-medium schools has been less successful, often due to its confinement to the Welsh (as a subject) lessons (WJEC, 2015). In an attempt to reverse this trend, and to help move one step closer towards realising the Welsh Government’s goal of doubling the number of Welsh speakers to a million by 2050 (Welsh Government, 2017), a number of different language-based strategies have or are currently being implemented in English-medium schools in order to help raise pupils’ awareness of Welsh and increase their Welsh language abilities. One particular strategy that has been implemented widely across the secondary school sector is Incidental Welsh (IW) (Davies, 2012). IW requires teachers; native speakers and learners alike, to deliver everyday Welsh vocabulary and phrases as part of their subject lesson, whatever the subject of the lesson may be. However, in many cases, reluctant speakers of Welsh or those who have little or no Welsh language skills (other than the ability to deliver a set of words and phrases to their pupils) lack the necessary confidence and/or skills that are required for the successful implementation of IW. Drawing on data from classroom observations, questionnaires and focus groups, this study explores the impact of formal language support sessions, which are typically tailored to individual teacher needs, on raising teacher confidence in implementing Welsh across the curriculum. Whilst there are heavy resource implications attached to this type of strategy, the results support the need to empower teachers with skills and confidence in integrating language and content.