There have been studies done at each phase of its evolution, but much has been focused on how aspects of Nheengatu, such as its grammar or phonology, have changed upon contact over the years. (Facundes et al. 1994 and Rodrigues 1958, 1986). As mentioned earlier, the first documents that were produced were by Jesuit missionaries in the 16th and 17th centuries, such as "Arte da Grammatica da Lingoa mais usada na costa do Brasil" by Father José de Anchieta (1595) and "Arte da Língua Brasilíca" by Luis Figueira (1621). These were detailed grammars that served their religious purposes. Multiple dictionaries have also been written over the years (Mello 1967, Grenand and Epaminondas 1989, Barbosa 1951). More recently, Stradelli (2014) also published a Portuguese-Nheengatu dictionary. There have also been several linguistic studies of Nheengatu more recently, such as Borges (1991)’s thesis on Nheengatu phonology and Cruz (2011)’s detailed paper on the phonology and grammar of Nheengatu. She also studied the rise of number agreement in modern Nheengatu, by analyzing how grammaticalization occurred over the course of its evolution from Tupinambá (Cruz 2015). Cruz (2014) also studies reduplication in Nheengatu in detail, as well as morphological fission in bitransitive constructions. A proper textbook for the conducting of Nheengatu classes has also been written. (Navarro 2011). Lima and Sirvana (2017) provides a sociolinguistic study of Nheengatu in the Pisasu Sarusawa community of the Baré people, in Manaus, Amazonas. Language documentation agencies (such as SOAS, Museu do Índio, Museu Goeldi and Dobes) are currently not engaged in any language documentation project for Nheengatu. However, research on Nheengatu by Moore (1994) was supported by Museu Goeldi and the Brazilian National Research Council (CNPq), and funded by the Society for the Study of the Indigenous Languages of the Americas (SSILA) and the Inter-American Foundation. In this study, Moore focused on the effects of language contact, and how Nheegatu evolved over the years with the help of a Nheegatu-speaking informant.