War and the resulting economic turmoil. English gradually began to replace Welsh as the community language, as shown by the decline of the Welsh language press in the town. This pattern continued after the Second World War despite the advent of Welsh medium education. Ysgol Gymraeg Aberdâr, the Welsh-medium primary school, was established in the 1950s with Idwal Rees as head teacher. According to the 2011 Census, 11.6% of Aberdare residents aged three years and over can speak Welsh, with 24.8% of 3- to 15-year-olds stating that they can speak it. Industry Iron Industry Ironworks were established at Llwydcoed and Abernant in 1799 and 1800 respectively, followed by others at Gadlys and Aberaman in 1827 and 1847. The iron industry began to expand in a significant way around 1818 when the Crawshay family of Merthyr purchased the Hirwaun ironworks and place them under independent management. In the following year, Rowland Fothergill took over the ironworks at Abernant and a few years later did the same at Llwydcoed. Both concerns later fell into the hands of his nephew Richard Fothergill. The Gadlys Ironworks was established in 1827 by Matthew Wayne, who had previously managed the Cyfarthfa ironworks at Merthyr. The Gadlys works, now considered an important archaeological site, originally comprised four blast furnaces, inner forges, rowing mills and puddling furnaces. The development of these works provided impetus to the growth of Aberdare as a nucleated town. The iron industry was gradually superseded by coal and all the five iron works had closed by 1875, as the local supply of iron ore was inadequate to meet the ever-increasing demand created by the invention of steel, and as a result the importing of ore proved more profitable. Coal industry The iron industry had a relatively small impact upon the economy of Aberdare and in 1831 only 1.2% of the population was employed in manufacturing, as opposed to 19.8% in neighbouring Merthyr Tydfil. In the early years of Aberdare's development, most of the coal worked in the parish was coking coal, and was consumed locally, chiefly in the ironworks. Although the Gadlys works was small in comparison with the other ironworks it became significant as the Waynes also became involved in the production of sale coal. In 1836, this activity led to the exploitation of the "Four-foot Seam" of high-calorific value steam coal began, and pits were sunk in rapid succession. In 1840, Thomas