There are other traces of vowel harmony in modern Korean: many native Korean words tend to follow vowel harmony such as (, 'person'), and (, 'kitchen'). Mongolian Mongolian exhibits both a tongue root harmony and a rounding harmony. In particular, the tongue root harmony involves the vowels: (+RTR) and (-RTR). The vowel is phonetically similar to the -RTR vowels. However, it is largely transparent to vowel harmony. Rounding harmony only affects the open vowels, . Some sources refer to the primary harmonization dimension as pharyngealization or patalalness (among others), but neither of these is technically correct. Likewise, referring to ±RTR as the sole defining feature of vowel categories in Mongolian is not fully accurate either. In any case, the two vowel categories differ primarily with regards to tongue root position, and ±RTR is a convenient and fairly accurate descriptor for the articulatory parameters involved. Turkic languages Turkic languages inherit their systems of vowel harmony from Proto-Turkic, which already had a fully developed system. The one exception is Uzbek, which has lost its vowel harmony due to extensive Persian influence; however, its closest relative, Uyghur, has retained Turkic vowel harmony. Azerbaijani Azerbaijani's system of vowel harmony has both front/back and rounded/unrounded vowels. Tatar Tatar has no neutral vowels. The vowel é is found only in loanwords. Other vowels also could be found in loanwords, but they are seen as Back vowels. Tatar language also has a rounding harmony, but it is not represented in writing. O and ö could be written only in the first syllable, but vowels they mark could be pronounced in the place where ı and e are written. Kazakh Kazakh's system of vowel harmony is primarily a front/back system, but there is also a system of rounding harmony that is not represented by the orthography. Kyrgyz Kyrgyz's system of vowel harmony is primarily a front/back system, but there is also a system of rounding harmony, which strongly resembles that of Kazakh. Turkish Turkish has a 2-dimensional vowel harmony system, where vowels are characterised by two features: [±front] and [±rounded]. There are two sets of vocal harmony systems: a simple one and a complex one. The simple one is concerned with the low vowels e, a and has only the [±front] feature (e front vs a back). The complex one is concerned with the high vowels i, ü, ı, u and has both [±front] and [±rounded] features (i