Difficulties of phonetics are:
(1) Multiplicity of sounds to be produced, including many sounds and combinations that do not occur in the language of the learner.
(2) Variation of accent, and of sounds expressed by the same letter.
These difficulties are both eliminated in Esperanto.
(1) Relatively few sounds are adopted into the language, and only such as are common to nearly all languages. For instance, there are only five full vowels and three1 diphthongs, which can be explained to every speaker in terms of his own language. All the modified vowels, closed "u's" and "e's," half tones, longs and shorts, open and closed vowels, etc., which form the chief bugbear in correct pronunciation, and often render the foreigner unintelligible—all these disappear.
1Omitting the rare eŭ. ej and uj are merely simple vowels plus consonantal j (= English y).
(2) There is no variation of accent or of sound expressed by
the same letter. The principle "one letter, one sound"1 is adhered to absolutely. Thus, having learned one simple rule for accent (always on the last syllable but one), and the uniform sound corresponding to each letter, no mistake is possible.
1The converse—"one sound, one letter"—is also true, except that the same sound is expressed by c and ts. (See [Appendix C].)
Contrast this with English. Miss Soames gives twenty-one ways of writing the same sound. Here they are: