Types of hierarchies of pronunciation difficulty are discussed, and a hierarchy based on contrastive analysis plus informal observation is proposed. This hierarchy is less one of initial difficulty than of error persistence. One feature of this hierarchy is that, because of lesser learner awareness and very limited functional load, errors involving allophones are more persistent than errors involving phonemes. Phonetic difficulty and suprasegmental and spelling interference are aggravating factors that increase the relative difficulty of particular problems in the hierarchy. To test the proposed hierarchy and three other hypotheses, a thorough pronunciation test was administered to 50 English-speaking students of Spanish (almost all of whom also knew some French). The test was given at the end of 45 hours of mostly oral instruction, which included 4 to 5 hours of specifically pronunciation instruction. The resulting data formed the basis for error analysis. The results generally confirmed the proposed hierarchy; they also showed the "sacredness" of word boundaries for speakers of English, the negative effects of spelling on pronunciation, greater frequency of errors in cognate than in non-cognate words, evidence of suprasegmental interference, and more frequent errors with known words than with unknown words. Conclusions include several suggestions for the teaching of Spanish pronunciation. (Author/CLK)