Wittnann相信里昂手语、西班牙手语、巴西手语和委内瑞拉手语并不属于法国手语语系,但确实有因刺激扩散产生的关联,而且是里昂手语启发了比利时手语。智利手语 (1852)也一般认为属于法国手语语系,但Wittmann没有列出。[來源請求]夏威夷手语(可能带当地混合)是孤立语言。[來源請求]J. Albert Bickford总结道,“并没有[里昂手语]曾存在过的实质证据”,《民族语》也于2017年将其编号撤回。[8]
Hammarström, Harald; Forkel, Robert; Haspelmath, Martin; Bank, Sebastian (编). LSFic. Glottolog 2.7. Jena: Max Planck Institute for the Science of Human History. 2016.
Lloyd Anderson & David Peterson, 1979, A comparison of some American, British, Australian, and Swedish signs: evidence on historical changes in signs and some family relationships of sign languages
Wittmann, Henri (1991). "Classification linguistique des langues signées non vocalement." Revue québécoise de linguistique théorique et appliquée 10:1.215–88.[1] (页面存档备份,存于互联网档案馆)
McCaskill, Carolyn, Ceil Lucas, Robert Bayley, and Joseph Hill. 2011. The Hidden Treasure of Black ASL: Its History and Structure. Washington, D.C.: Gallaudet University Press. ISBN978-1-56368-489-0.