Esperanto is a constructed international auxiliary language designed to have a simple phonology. The creator of Esperanto, L. L. Zamenhof, described Esperanto pronunciation by comparing the sounds of Esperanto with the sounds of several major European languages. With over a century of use, Esperanto has developed a phonological norm, including accepted details of phonetics, phonotactics, and intonation, so that it is now possible to speak of proper Esperanto pronunciation and of properly formed words independently of the languages originally used to describe it. This norm accepts only minor allophonic variation. Inventory The original Esperanto lexicon contains: 23 consonants (including ĥ , which has become rare, and 4 affricates) 11 vowels (5 simple vowels and 6 diphthongs). A few additional sounds found in loan words, such as , are not stable. Consonants The uncommon affricate does not have a distinct letter in the orthography, but is written with the digraph , as in ('husband'). Not everyone agrees with Kalocsay & Waringhien that and are a near rhyme, differing only in voicing, or on the status of as a phoneme; Wennergren considers it to be a simple sequence of /d/ + /z/. The phoneme has been largely replaced with /k/ and is now found mostly in loanwords and a very few established words such as ('a Czech'; cf. 'a check'). The letter ŭ is sometimes used as a consonant in onomatopoeia and unassimilated foreign names, in addition to the second element in diphthongs, which some argue is consonantal /w/ rather than vocalic (see below). Vowels Esperanto has between 5 and 11 vowels, depending on analysis: 5 monophthongs and up to 6 diphthongs. There are six historically stable diphthongs: , , , and , . However, some authors such as John C. Wells regard them as vowel–consonant sequences – , , , , , – while Wennergren regards , , , as vowel–consonant sequences and only , as diphthongs, there otherwise being no in Esperanto. Origins The Esperanto sound inventory and phonotactics are very close to those of Yiddish, Belarusian and Polish, which were personally important to Zamenhof, the creator of Esperanto. The primary difference is the absence of palatalization, although this was present in Proto-Esperanto (, now 'nations'; , now 'family') and arguably survives marginally in the affectionate suffixes and , and in the interjection Apart from this, the consonant inventory is identical to that of Eastern Yiddish. Minor differences from Belarusian