The Selkup people used the word Ytid (ödeD and other phonetic variants), the Ket people used the word yed´ for the conception "spring". The famous hungarian researcher Haidu P. supposed, that the selkup word has been borrowed from the Yenissey languages: nen. djotti, selk. ödeD < ket. Yed (spring) .
The prominent researcher of the Yenissey languages Joki A. expressed the same opinion, that the samoyed words with the meaning "spring" has been borrowed from the Yenissey languages, there are the following correspondence at that: selk. ödəD - ket - yed´,yedi - tib. - dpyid .
The well known researcher K. Bouda has the opposite view on the borrowing direction, namely: yen. yed(i); kott. iji - spring < sam. ytid .
The words with the meaning "winter" were fixed in the Samoyed and the Yenissey languages. There is the supposition, that the selkup kä, ke, kam. khä had been borrowed from Yenissey. From the E. Levi´s point of view there are the equivalents: ket. kete, kott. kēti, tib. dgun . Some researchers express the contrary idea: the yenissey root had been borrowed from the Samoyed language [4, 5].
Thus, contradictory linguistic data concerning the borrowing processes of words "spring", "winter" in the Samoyed and the Yenissey languages have been demonstrated above. Concerning some opinions about relations of the Samoyeds and Yenisseys it may be supposed the following peculiarities of the origin of the names for conceptions "spring", "winter" in the Samoyed (Selkup) and the Yenissey (Ket) languages:
- The words "winter", "spring" had been borrowed by native speakers from each other during the period of the existence of Samoyed and Yenissey linguistic communities.
- The words "winter", "spring" had been borrowed by native speakers from each other after the disintegration of indicated linguistic communities (or one of them).
- The words "winter", "spring" have been borrowed by native speakers not from each other, but from another source.
It is known that there are many words in Selkup and Ket borrowed from other, unrelated languages. For example, words from Russian and Turkic have been fixed in the Selkup language. A whole number of common words of Ket and Chinese have been revealed as well . The hypothesis about the connection of the Yenissey and the Tibetan-Chinese languages, based on the study of similar words, has been supported by many authors . The famous researcher of aboriginal Siberian languages A.P. Dulzon has noted the correspondence between the words of the Ket and the Hun languages in addition .
The observed lexical equivalence and correspondences are the basis for the supposition about the available contacts between native speakers of above stated languages. There is the opinion about the connection between the Kets and the Chineses, the Kets and the Huns, (in addition between the Kets and American Indians too), etc. 
From the other side there is the supposition that the Samoyed and the Yenissey had the common ancient ancestral home situated in the south Siberia . There is the idea about the single ancient cultural-linguistic community of Selkups and Kets .
It is possible to think about possible ancient contacts not only between the Yenissey (Kets) and Tibetans, Chineses, Huns, but between the Samoyeds and these three peoples. Therefore the words "winter", "spring" in Samoyed (and in Yenissey) could be borrowed from languages of Tibetans, Chineses, Huns.
4) The above mentioned words "winter", "spring" are unrelated.
There is the assumption that the Samoyed word roots with the meaning "winter" (selk. kə, kamas. khä) have nothing to do with the yenissey root *gəte - "winter" .
So, the research of the calendar names with the meaning "winter", "spring" in Samoyed (Selkup) and Yenissey (Ket) are connected with some different and sometimes conflicting conclusions.
Thus, it is impossible to identify the true origin of calendar names in above mentioned pre-literate languages on the basis of only linguistic data. The forming of words with the meaning "winter", "spring" can be found out by means of the integrated approach. This approach consists in the synthesis of many different techniques and data, concerning: linguistic, ethnographical, historical, philosophical etc. This approach covers both the Samoyed (Selkup) and the Yenissey (Ket) (and other peoples). It means the detailed study of the vocabulary, semantic, phonetic, borrowing and other processes in languages of these peoples, the comparative research of their social and economical structure, of the material culture traits, of the thinking type, of the territorial and climate life peculiarities, the investigation of the ancient relations between the pre-literate Siberian peoples and the analysis of many other facts. This method will permit to understand the true origin of indicated words. So, the research of calendar names in the Selkup and the Ket languages causes the general study of many-sided ancient cultural - linguistic contacts of many Siberian indigenous peoples.
- Kostyakov M.M. Yenissey-samoyed lexical groups // Soviet Finnougristic. - XX. - 1984. - № 3 - pp. 199-206
- Toporov V.N. The Ket language bibliography // Ket collection. - Moscow: Science. - 1969. - pp. 243-283
- Bouda K. The Yenissey Language. Genealogical and morphological study // Anthropos. - V. 52. - 1957. - 134 P.
- Starostin S.A. Protoyenissey reconstruction and external relations of the Yenissey languages // Ket collection. - Leningrad: Science. - 1982. - pp. 144-237
- Polyakov V.A. Methods of the lexic nomination in the Yenissey languages // Novosibirsk: Science. - 1987. - pp. 66-80
- Ivanov V.V., Toporov V.N., Uspenskiy B.A. Preface // Ket collection. Linguistics. - M., 1968. - pp. 5-14
- Dulzon A.P. Huns and Kets // Siberian branch of the USSR Academy of Science Bulletin. - Novosibirsk: Science. - 1968. - №11. - pp. 137-142
- Prokofyev G.N. Turukhan Ostyak-Samoyed // Ethnography. - Moscow-Leningrad: State publishing house. - 1926. - book VI. - pp. 96-103
- yen. -Yenissey
- kam. - Kamass
- kot. - Kot
- nen. - Nenets
- sam. - Samoyed
- selk. - Selkup
- tib. - Tibetian