Orkhon Turkic is the oldest Turkic dialect whose written records have come down to us. Many parts of the Kül Tegin and Bilgä Kagan inscriptions are almost identical with each other. Although most parts of these inscriptions are well understood, some parts like the letter group čẄlgl (or čẄlgIl) in the passage YWGčI : sIGTčI : ẄŋrA : ẅkẄn (or kẄn) : TWGSKDA : bẄklI : čẄlgl (or čẄlgIl) : TBGč : tẄpẄt : pR : pWRm (or pRpWRm) : ïK IRKz : Ẅč wK WRIKN : WTzTTR : ïK ITñ : TTBI : BWnčA : BWDN : klpn : SIGTAms (or sIGTAmš): YWGLAms (or YWGLAmš) of KT E 4 and in BK E 5 are not so. This passage has been interpreted differently by the researchers. All/most of the researchers overlooked the following points:
- There were two Tabγač states in northern China in the early years of the Turkic Khaganate;
- There is a plain rather than a steppe or desert in the Liao River basin of Manchuria;
- The mark resembling a colon (:) is used to separate words and word groups from each other.
The Turkic Khaganate (552 ~ 744) was established by the Ashina clan of the Köktürks under the leadership of Bumïn Kagan (d. 552). Ištämi was a younger brother of Bumïn Kagan. In 552 ~ 576, as a yabgu he was the ruler of the western part of the Turkic Khaganate, the Western Turkic Khaganate. At that time, there were two Tabγač states in northern China, i.e. the Northern Qi (北齊 Běi Qí; 550 ~ 577; simply 齊 Qí) and the Northern Zhou (北周 Bĕi Zhōu; 556 ~ 581; simply 周 Zhōu). These two Tabγač states should have sent representatives to Ištämi Kagan’s funeral. Therefore, čẄlgl (or čẄlgIl) and TBGč must correspond to the Northern Qi and the Northern Zhou. All of the researchers overlooked this point till now.
Most of the researchers wanted to relate čẄlgl (or čẄlgIl) to čöl ‘desert’ or ‘steppe’. However, there is a plain rather than a steppe or desert in the Liao River basin of Manchuria. Therefore, it is almost impossible to relate čẄlgl (or čẄlgIl) to čöl ‘desert’ or ‘steppe’. The word for ‘plain’ is yazï in the Orkhon inscriptions.
It is problematic to read only bẄklI : čẄlgl (or čẄlgIl) together in this passage, because the mark resembling a colon (:) is used to separate words and word groups from each other.
In my opinion, the Köktürks should have distinguished two Tabγač states by calling one state čẄlgl (or čẄlgIl) and the other state Tabγač. In all probability, čẄlgl (or čẄlgIl) and Tabγač are the Northern Zhou and the Northern Qi respectively. If so, čẄlgl (or čẄlgIl) can be analyzed as Čülüg el ‘realm/country of the Čü people’ (< Čü (<周 Zhōu) + -lüg ‘suffix forming possessive noun/adjective’ + el ‘realm/country’). As Erdal (1991: 144) writes, this +lXg is added also to the proper names of places, as it is to this day. Thus, Čülüg el is the first example of the +lXg added to the proper names of places. Now, the letter groups bẄklI : čẄlgl (or čẄlgIl): TBGč in this passage should be read as Bökküli, Čülüg el, Tabγač “Bökküli (= Goguryeo), Čülüg el (= the Northern Zhou), Tabγač (= the Northern Qi)”.