The Sumerian language is not an isolate language. 160 years of articles and books prove this fact.
First of all, the origins of Sumerians were established by those who had discovered this ancient civilization lost in history for 4000 years until 1850: British scholar Edward Hincks and Henry Rawlinson classified this new language and the people as Turkic (Turanian) and their origins as Central Asia in the 1850s. So, the idea of Sumerians being Turks is not a novel fact!
(Linguistic proofs must be considered together with Archaeological, Cultural, Mythological, Genetic and other proofs: see Sumerian origins for details)
Frenchman Jules Oppert who named this civilization as Sumer (could it have been Subar?) and other Oriental Studies scholars including Edwin Norris, Niels Westergaard, Finnish scholar Wilhelm Lagus (article by Finnish linguist Tapani Harvianen) have agreed. They were referring to Turkic people as Scythian while others referred to them as Turanian. (Later, the word Turanian or Turanid was replaced by Ural Altaic in Western academic circles.)
1850s A very important 2011 article by Professor Kevin J. Cathcart explains how Sumerian cuneiform was deciphered by Edward Hincks as well as the role of Rawlinson in the discovery of Sumer.
1874 French Orientalist Francois Lenormant analyzed Turkic-Sumerian mythology by comparing Sumerian myths with Central Asian magic and cultural similarities, in addition to comparing Sumerian language with Ural-Altaic languages. He published his book La magie chez les chaldeens et les origines accadiennes concluding Sumerian to be Turanian.
1874 It was well established in European circles that Sumerians were Turanian (Turkic) for almost 20 years until Joseph Halevy declared in 1874 that there was no such language as Sumerian!
He purported in many "academic papers" that the newly discovered language was a secret Babylonian priest communication protocol and not a real language! Unfortunately this was a ridiculous assertion/lie but very tellingly, most European scholars except Francois Lenormant and Oppert played along! And the Sumerian studies were largely hindered (except the works of Hungarian scholars) until 1915!
1915 Renowned German Assyriologist Fritz Hommel showed that 200 Sumerian words were Turkic
1930s It was Ataturk who in the 1930s invited scholars from Europe and Turkey to Ankara to study the subject and then adding his own linguistic and history work of almost 5 years, showing Sumerians to be Turkic and of Central Asian origin. He also said that Anatolia (Turkey) was the land of the Turks for 7000 years. And since then many linguistic, archaeological, ethnological, genetic and geographic articles and books firmly established Sumerian as Turkic many times over!
1975 A major paper and warning to scholars was published: Transliteration of Sumerian Problems and Prospects by famed Assyriologist Simo Parpola In: I Karky (Ed.) Studia Orientalica 46
IMPORTANT NOTE: This was exactly Ataturk's thoughts some 40 years before Parpola. He knew transliteration through an Afro-Asiatic (Semitic) language created errors especially in phonetics. That is why when Turkish researchers wanted to establish a department of Assyriology just like in the West (hence copying the West) Ataturk countered them by founding a department of Sumerology in the 1930s! It was the very first in the world and unfortunately 80 years later it is still the only one, though completely co-opted by Western falsehoods!
1979 The first paper is published (in Turkish) that discusses Sumer civilization together with its neighbors stating Sumer people are Turks! It is a seminal work in the Turkish language by Vecihe Hatiboglu the first and still the only known Turkish scholar to go in the footsteps of Ataturk.
1990 Osman Nedim Tuna analyzes Sumerian words and shows equivalence of 165 Sumerian and Turkish cognates. He also makes a rough calculation about the age of the Turkish language, asserting it to be 4000 years old, at least
1999 The book "And the Whole World was One Language" by Selahi Diker asserts that Sumerian is a Turkic language and that many other archaic languages are derived from Turkic.
2003 The Development of Writing from Pictography to Logography (Logographics) Sumer Turkic Accordances and Graphic Logograms by Kazak researcher Amanjolov
2003 The book 5000 yillik Sumer Turk Baglari (5000 years of Sumerian-Turkic relations) by Azarbaijani researcher Begmyrat Gerey is available online on his website in pdf, for free in the Azeri dialect. A Turkey's Turkish version is also available for free The book compares archaeological evidence, cultural parallels, mythologic similarities and linguistic data to come up with a definitive proof of genetic relation.
2007 The book by engineer and ancient language researcher Mehmet Unal Mutlu Dunya Uygarliklarinda Turk Dili ve Kenger Uygarligi is published. (I did not read the book but only the excerpts in Turkish)
2007 Important and surprising paper by famed Finnish Assyriogist Simo Parpola presents the results of the Sumerian Uralic word comparison results to the World Assyriology Congress in Moscow.
He states that he went through 75% of the Sumerian vocabulary and he found out that 1700 words are Uralic, most of them being words from Turkic languages! He says a genetic relationship with Turkish seems possible. THE PROBLEM with the presentation: Turkish is NOT classified as a Uralic language! If most of the basic word and grammatical morpheme matches are with Turkic languages then why didn't he say that Sumer was a Turkic language and instead opted for Uralic which does not include Turkish?
2013 Another important paper corrected some of the phonetic mistakes prevalent in current Sumerian transliterations and studies. Yet Another Suggestion about the Origins of the Sumerian Language by Greek researchers Ioannis Kenanidis, Evangelos C. Papakitsos. PROBLEM with the article: He compares Sumerian words to Turkish words and then states in the conclusion that Sumerian is r-Altaic. There is no such language as r-Altaic there is Ogur Turkic (Turks call it r-Turkish)!
2013 Dubbed as the Last Sumerian Queen, centenarian Sumerologist Muazzez Ilmiye Cig publishes a very important book: Sumerler Turklerin Bir Koludur (Sumerians are a Turkic People). In Turkish only.
2014 Comparison of Akkadian and Turkish by Azerbaijani Efsad Alili. An important article that discusses the relationship of Afroasiatic (Semitic) Akkadian with Turkish.
A telling remark in the paper: "Today Assyriology scholars have little or no knowledge of Turkish Grammar, whereas the first generation of experts who deciphered the Mesopotamian ideograms and cuneiform writings were familiar with the Ugro-Altaic languages."
2015 This is a refreshing article by Turkish scholars Suleyman Eratalay and Sevda Eratalay that compares the grammatical features of Sumerian and Turkish: The Syntactic Equivalence between Sumerian and Turkish
2016 Famed Finnish Assyriologist Simo Parpola published Etymological Dictionary of Sumerian Language. This is a first in the world in terms of scope and seems to be a very important and groundbreaking book! It is the highest academic declaration in the 21st century stating that Sumerian is not a language isolate. (The only objection I have: Uralic classification, instead of Turkic, is wrong)
2016 My book Sumerian Turks: Civilization's Journey from Siberia to Mesopotamia by Mehmet Kurtkaya is the ultimate proof of Sumerian origins. All related literature since the 1850s plus all social, cultural, econopolitical and geographical aspects including their much ignored neighbors! Groundbreaking suggestions/corrections on Hurrian, Scythians, Hatti / Hittite, Goth, Gut / Gutians, Ogur and Oguz Turks, Turukku and their relations to Sumerians based on already publicly available cuneiform info.