The extended etymology for Ego, Εγώ ( I )
The Oxford Etymologic Dictionary (OED) considers Ego / I as if it were a self-standing word developed within the Germanic and 'Indo-European' languages with a mere meaning of 'I / me / self, myself':[Spoiler (click to open)]
I (pron.)
12c., a shortening of Old English ic, the first person singular nominative pronoun, from Proto-Germanic *ek (source also of Old Frisian ik, Old Norse ek, Norwegian eg, Danish jeg, Old High German ih, German ich, Gothic ik), from PIE *eg- "I," nominative form of the first person singular pronoun (source also of Sanskrit aham, Hittite uk, Latin ego (source of French Je), Greek ego, Russian ja, Lithuanian aš).
Reduced to i by mid-12c. in northern England, later everywhere; the form ich or ik, especially before vowels, lingered in northern England until c. 1400 and survived in southern dialects until 18c. It began to be capitalized mid-13c. to mark it as a distinct word and avoid misreading in handwritten manuscripts.
https://www.etymonline.com/word/I
ego (n.) by 1707, in metaphysics, "the self; that which feels, acts, or thinks," from Latin ego "I" (cognate with Old English ic; see I); its use is implied in egoity.
https://www.etymonline.com/word/ego
местоим., укр. я, др.-русск. язъ, я (и то и другое - в Мстислав. грам. 1130 г.; см. Обнорский - Бархударов I, 33), ц.-сл. азъ ἐγώ, реже ѩзъ (см. Дильс, Aksl. Gr. 77), болг. аз, яз (Младенов 702), сербохорв. jа̑, словен. jàz, jâ, чеш. já, др.-чеш. jáz (совр. чеш. форма - с начала ХIV в.), слвц. jа, др.-пол. jaz, пол., в.-луж., н.-луж. jа, полаб. joz, jо.
Праслав. *аzъ отличается своим вокализмом от родственных форм, ср. др.-лит. еš, лит. àš, лтш. еs, др.-прус. еs, аs, др.-инд. ahám, авест. azǝm, др.-перс. аdаm, арм. еs, венет. еχо, гр. ἐγώ, лат. еgо, гот. ik "я". Наряду с и.-е. *еǵ- (гр., лат., герм.), существовало и.-е. диал. *eǵh- (др.-инд., венет.). Недоказанной является гипотеза о существовании *ō̆go наряду с *еgō на основе слав. аzъ и хетт. uk, ug "я" (Мейе - Эрну 342 и сл.; см. Вальде - Гофм. I, 395 и сл.). Не объяснена еще достоверно утрата конечного -z в слав.; весьма невероятно, чтобы она совершилась по аналогии местоим. tу (напр., Ягич, AfslPh 23, 543; Голуб - Копечный 147), а также чтобы долгота начального гласного была обусловлена долготой гласного в tу (Бругман у Бернекера, см. ниже). Более удачна попытка объяснения аzъ из сочетания а ězъ (Бернекер I, 35; Бругман, Grdr. 2, 2, 382), но см. против этого Кнутссон, ZfslPh 12, 96 и сл. По мнению Зубатого (LF 36, 345 и сл.), в этом а- представлена усилит. част. *ā, ср. др.-инд. ād, авест. āt̃, ср. также др.-инд. межд. ḗt "смотри, глядь!" из ā и id; Педерсен (KZ 38, 317) видит здесь влияние окончания 1 л. ед. ч. -ō; сомнения по этому поводу см. у Бернекера (I, 35). Для объяснения -z привлекают законы сандхи (Сольмсен, KZ 29, 79); ср. Бернекер, там же; И. Шмидт, KZ 36, 408 и сл.; Вакернагель - Дебруннер 3, 454 и сл.
http://www.classes.ru/all-russian/russian-dictionary-Vasmer-term-17126.htm
ich (Ger.), Εγώ [ego] (Gr.), ego (Lat.), io (Ital.), yo (Sp.), I (Eng.), jag (Sw.), я [ja] (Slavic)...
However, should one look beyond the hypothetic *constructions, established by the German philologists in the 19th Century, one would see an obvious Nostratic relation of the above words with the meaning of ' I ' to the following words with the meaning of ' 1 (one)':
[isch, ish] (Hebrew) - a sole person, a single man.
egy (Hung.) - one;
އެކެއް [ekeḣ] (Divehi, Maldives) - one;
ekahi (Hawayan) - one;
[eka] (Sanskrit) - one, sole, single;
एक [ek] (Hindi), এক [ek] (Bengal.), एक [eka] (Marathi), [eka] (Pali), یوअख [akʰ] (Kashmiri), [ikk] (Punjabi) - one;
ایک [ik] (Urdu), یِک [yek] (Pers.), یهک [yek, êk] (Kurdish), як [yak] (Tajik), ек (Tat, Iranian), екх [ekh] (Gipsy) - one;
нэг [neg] (Mongol.) - one;
aiquen (Nauru) - one;
[huk, suk, jujj] (Kechua) - one;
壱 [ichi] (Jap.) - one;
ik, ikte, ик, икте, икыт (Mari) - one;
એકડો [ekaddo] (Gujarati) - one;
э̄ххт [eehht] (Kildin Saami), okta (Saami), ak, akw, ак, аква (Mansi) - one;
ühe (Est.) - sole, single, mono-; üks, ühe, üht (Est., Izhora), ikš, ükš (Livon.), yksi (Fin.), üksi (Karel.), ükš (Lüdic, Vepssian) - one.
[eka] (colloquial Finnish) - first.
And first is also the elder, the senior:
ugu (Sumerian) - ancestor;
aikamies (Fin.) - an aged, adult person;
ukko (Fin.) - the old man, the grandfather, the forefather; akka (Fin.) - the foremother;
Ukko, or Äijä or Äijö parallel in Estonian mythology to Uku, is the god of the sky, weather, harvest and thunder in Finnish mythology. https://en.wikipedia.org/wiki/Ukko
kääkkä (Finnish) - an old man or a woman, older than Ukko, Äijä and Akka;
vecchio (Ital.) - old, elder;
vecākā f., vecākais m. (Latvian) - elder;
вуйко [vuyko] (Ukrainian), wujek (Polish), ујак [ujak] (Serbian, Croatian) - mother's uncle; polite addressing of an elder person; вуйко [vuyko] (Guzul) - a bear;
baka (Bosnian, Croatian) - grandmother;
γιαγιά (Gr.) - grandmother;
agg aggastyán (Hun.) - very old person;
aka, ağa (Tukish) - an elder brother; a(village) headman; the master; the lord; ага [aga] (Tatar) - an uncle, a venerable (revered) person, a respectable husband; аға [agha] (Kazakh) - a senior person; an elder brother; an elder relative; an uncle along the line of the father; the respected oldest man; ағай [aghay] (Kaz.) - an uncle; a respectful appeal to an elder person;
аке [ake] (Kirgyz) - uncle; аганы [agany] (Kirgyz) - elder brother; akaa (Pashtu) - uncle, old man;
әже [äje] (Kazakh) - grandmother;
አጎት [āgoti] (Amharic language of Ethiopia) - uncle;
aki (Sudan dialect of Arabic) - grandfather; kokolot (Sudan) - elder;
agogo, gogo (Chichewa Bantu language in Southern Africa) - grandfather, great-grandfather, grandmother, great-grandmother; ugogo (Zulu) - grandmother; akulu (Chichewa) - senior;
kakan (Hausa language in Western Africa) - grandfather, grandmother; oga (Yoruba language in Nigeria), agadi, okenye (Igbo language in Nigeria) - elder, senior;
kagan (hakan, Mong. Qaɣan, kaan, haan, Chinese 可汗 [Kè hán]) - the highest title of a sovereign in the medieval nomadic hierarchy, the Khan of Khans, the great Khan;
ах [ah] (Mongolian) - elder brother; эгч [egch] (Mong.) - elder sister;
哥哥[gēgē] (Chinese) - elder brother;
[ak, akā, akai] (Dravidian) - elder relative; [akka] (Malayalam Dravidian) - elder sister, wife of an elder brother, elderly maternal or paternal cousin; ಅಕ್ಕ [akka] (Kannada), [akkë] (Kodagu), [akka, akkè] (Tulu Dravidian), అక్క [akka] (Telugu) - elder sister; [ukko, akko] (Gondi, a language in India) - mother’s grandfather;
ಅಜ್ಜ [ajja] (Kannada), आजोबा [Ājōbā] (Marathi) - grandfather; ಅಜ್ಜಿ [ajji] (Kannada), आजी [ājī] (Marathi), ආච්චි, ආච්චි අම්මා [ācci, ācci ammā] (Sinhalese) - grandmother;
કાકા [kākā] (Gujarati), काका [kākā] (Marathi), चाचा [chaacha](Nepal, Hindi), চাচা [cācā] (Bengali) - uncle;
ukko (Tamil) - the old man; [akkā, akkai, akkan, akkāttai, akkāḷ, akkacci, akkaicci] (Tamil), අක්කා [akkā] (Sinhalese) - elder sister;
Bali-Aga - an ancient Balinese people, considered to be the indigenous and most ancient population of Bali, which appeared in Bali before the migration from Java of the main mass of Hindus at the times of the Majapahit empire ;
ยาย [yāy] (Thai) - grandmother; ใหญ่ [yāy] (Thai) - big, large, grand;
uyoan (Cebuan language in Philippines) - uncle; kuya (Philip.) - elder brother;
tuakana (Maori language in New Zealand) - elder brother;
toeaina (Samoa) - elder; tiyuhin (Philippines), tuagane (Samoa) - uncle;
kaikuaana (Hawaian) - elder brother, elder sister;
kakek (Indonesian) - grandfather; kakak (Indonesian) - elder brother;
käkäs (Kwagiutl, Kwak'wala language of North-American Indians) - grandfather;
[acan] (Maya) - mother's uncle; the husband of the father's sister; brother of mother’s grandfather; [akka] (Inuit) - paternal uncle; [akah] (Karok) - father;
Achamán - the supreme god of the Guanches on the island of Tenerife; the father-god and creator. The name means literally "(man) from heaven", hinting at the heavenly vault (sky). Compare back to: ég (Hung.) - sky, haven.
Learn about more relatives here: Semantic cluster around the word 'AGE' / 'YUGA'
https://new-etymology.livejournal.com/15774.html
N.B. The OED and Max Vasmer try 'to insert' the separate-standing Lithuanian AŠ ('I') and Church Slavic АЗ [AZ], into same cluster, as a variation of Я, I, EGO (having difficulty explaining the appearance of "Š", "Z").
AŠ and АЗ [AZ] belong, however, to the following very distinct separate Nostratic cluster (or sub-cluster):
[isa] (Arabic) - Jesus;
[ais] (Etruscan) - the God;
ōs, ēse (Old Eng.) - pagan God;
ǫ́ss, áss, ás, pl. æsir, fem. ásynja, pl. fem. ásynjur (Old Norse) - member of the main religious pantheon;
[az] (Gothic) - the God; the first, the beginning;
[az, yaz] (Old Polish) - the God;
isa (Est.) - the Father; the Senior person; the Ruler;
isä (Fin., Votic, Izhora), ižä, ižoi (Karel.), iža (Lüdic, Vepssian), áhčči (Saami), ńíśa (Nenets), eśi (Enets.), ďesi̮ (Nganasan), e̮sә (Sekulp.) - the Father;
oćä (Moksha) - the father's elder brother;
iza (Mari) - the elder brother;
ǟś (Mansi) - the mother's father;
ős (Hung.) - the Forefather;
[aš] (Sumer.) - one; to be in unity, in agreement; [ušu] (Sumer.) - one; sole, single;
ειϛ [eis] (Gr.) - one, sole, single, mono-;
asi(t) (Dravid.) - one;
ace (Eng.), As (Ger.), asso (Ital.) - the Ace (the highest playing card);
isa (Philippine) - one, sole, single, mono-;
азəы [azeo] (Abkhazian) - one;
азы [azy] (Church Slavic) - the primary basis.
In the end, all of the above words relate to the Rising Sun - and the Asia, the East - the place of the Rising Sun - learn more: https://new-etymology.livejournal.com/26253.html
And, yet another phonetic stem, with the similar gamma of meaninings (as always - ‘worldwide’ - regardless the artificial division of languages into language Groups, as the German phylologists of the 19th Century wanted it):
[en] (Maya) - I;
[én] (Hung.) - I;
unë (Albanian) - I;
[ani] (Hebrew), [ana] (Aram.) - I;
[inē] (Amkhar.) - I.
en (Dan., Sw.), ein (Ger.), uno (Ital.) - one (Eng.);
union (Eng.), unione (Ital.) - union;
unir(si) (Ital.), unite (Eng.) - unite, get joined, united (i.e. ‘get in one’).
ен [en] (Komi), ин [in] (Udmurt) - the Sky;
инмар [inmar] (Udmurt) - the God of the Skies, i.e., the Sun God (literally, ‘the Skies’ man’);
инь [in’] (Komi-Permian) - the woman, the wife; ань [an’] (Old Permian) - the Foremother;
[энь, онь; en’, on’] (Turkic) - high;
วัน [wan] (Thai) - the Day;
[an, on] (Egyptian) - the Sun;
анe [ane] (Ingushian) - the Sky; ану [anu] (Ingushian) - Heavenly, Godly, ‘of the Skies’;
ану-няке [anu-n’ake] (Ingushian) - person belonging to the Sky Genus, the God’s Family, to Di-nasty;
Anunnaki - in the Sumerian-Akkadian mythology, the Sky Gods who came to the Earth from the planet Nibiru;
[an] (Akkadian) - the God, the Lord, the Sovereign; adj. tall, great; [An-Ap] (Akkadian) - the God of the Skies;
[anu, ану] (Assyrian) - the God of the Skies; [anatu, anath] (Assyrian) - the Skies Goddess;
[an, am] (Sumerian) - the Skies; the Sky God;
[anak] - the race of giants who lived in Palestine;
[an] (Sanskrit) - the Air, the breathing; the Soul;
[aná] (Sanskrit) - the Eternal;
aina (Fin., Est., Votic), aena (dial. Fin.), ain (Izhora), ainos (Karel.), aino (Ludic) - eternal, eternally.
See further: the SUN - https://anti-fasmer.livejournal.com/135866.html :