recruits helped produce al-Shabaab's first English-language propaganda, and, thanks to its East African membership, Swahili remains the second most common language in al-Shabaab publications. Foreign fighters also have symbolic importance for al-Shabaab propaganda: al-Shabaab has intentionally played up the diversity of its recruits as a paean to its pan-Islamism – that is, to demonstrate that it transcends clannism and nationalism, embodying a united transnational ummah. Early surge Foreign recruitment peaked in the period between 2011 and 2013, which was also the period in which the phenomenon received the most attention. The 2006 Ethiopian invasion of Somalia attracted foreign volunteers to al-Shabaab's cause, and, as of 2010, al-Shabaab included an estimated 200–300 foreign fighters, not including a further 1,000 ethnic Somalis from the diaspora. In subsequent years, al-Shabaab recruitment became a concern for the governments of both the United Kingdom and the United States. At a security conference in London in 2010, the former head of MI5, Jonathan Evans, said that "a significant number of U.K. residents" were training with al-Shabaab; the precise number of British recruits was estimated at between 50 and 100 persons. There was also evidence that the group had received funding from Somali residents in Britain. Between 2012 and 2013, several British citizens faced control orders or even criminal charges related to association with al-Shabaab. Sweden, Denmark, Canada, and the U.S. similarly encountered evidence of citizens' affiliation with al-Shabaab. In the U.S., the U.S. Senate Homeland Security Committee heard as early as 2009 – from Michael Leiter, director of the National Counterterrorism Center – that American and other foreign fighters were being recruited and trained by al-Shabaab. In 2011, the House Committee on Homeland Security reported that more than 40 Muslim Americans and 20 Canadians had fought with al-Shabaab, and that at least 15 of those volunteers had been killed in Somalia. Later that year, a U.S. military official told the New York Times that about 30 U.S. citizens were al-Shabaab fighters. This was a resumption of an earlier trend of al-Shabaab recruitment among Americans, which previously had peaked in 2007–8. Also in 2011, two Somali Americans in Minnesota were convicted of illegally financing al-Shabaab. By mid-2013, observers believed that recruitment of U.S. citizens had subsided. In general, foreign activity in al-Shabaab has decreased, first, and perhaps most importantly, because the Syrian civil war became the focal point for foreign jihadist recruitment networks. Other factors, however, are