What is the primary phonological difference between dialects, vowels or consonants?

Question

Not considering things like vocabulary or syntax (if that is possible), what phonological differences make the most telling distinction between two dialects, is it the vowels or the consonants?

Informally, among English dialects, it seems that between any two things called dialects the major differences are the vowels (and the consonants seem to stay the same).

But I've heard (unsupported of course as is my personal judgement) that in other dialect families, it is a change in consonant (and not the vowel that marks the dialect difference) (the classic example being the 'shibboleth', an s/sh difference.

(of course this may be a false dichotomy, and there are other phonetic differences that are not about vowel/consonants, like say prosody or accent).

This question is somewhat motivated by my other question about lexical sets; that is an analysis technique for managing multiple varieties purely by vowels. Maybe that method is useful in general (in other sets of language varieties), or maybe it is just helpful for English, or maybe it is just one tool, and other tools are more or less successful (and I'd like to know to what degree).

Answer 1

There is no "primary" difference. Some examples from across the spectrum:

• Stops: one of the main differences people consciously identify between British English registers is the nature of stop releases. Fully released stops, even in word final position is characteristic of more deliberate and higher register speech, whereas stop glottalization or lack of release is common in lower registers.
• Fricatives: one of the most salient markets of the Taiwanese dialect of Chinese is the merger of alveolar sibilants with their retroflex counterparts.
• Approximants: broadly speaking, a major and easily identifiable difference between the Scottish dialect of English and RP is that in Scottish English, there is much less /r/-dropping.
• Vowels: vowel examples are probably the most common, but I wouldn't go as far as to say that they are the "primary" difference due to all the above examples. Probably the easiest isolated example of vowels being a cue of dialect is Canadian diphthong raising.

Moreover, each of the above can all contribute equally to non-native dialects:

• Stops: the inability of CV or CVN languages to adapt to CVC languages is a huge cue for non-nativeness; another prevalent example is when speakers of languages with obligatory word-final devoicing like German and Russian make homophonous word pairs like bat and bad (not exactly a stop contrast, since it's mostly vowel length, but it's complicated).
• Fricatives: since so many fricatives sound alike, fricatives are incredibly frequently pronounced differently for non-native speakers. Examples are substitution of /s/ for the cross-linguistically rare dental fricative found in English and the use of the velar /x/ in place of /h/ by speakers from languages without [h]. /h/ is also a common source of non-native accents. Since [h] is basically just loud breathing, it's non-distinctive in many languages. English speakers have a hard time adjusting to languages with contrastive word-final /h/, for instance, and French speakers have a hard time adjusting to languages with contrastive word-initial /h/.
• Approximants: conflation of /r/ and /l/ by Japanese and Korean speakers of English is all too well studied.
• Vowels: speakers will very often import vowel qualities from their native languages. For instance, English speakers learning any language with the pure high back rounded [u] will substitute the English centralized gliding equivalent.

There are also prosodic differences that influence our judgment of dialects, but I'm not experienced enough with them to advise on it intelligently.

In summary, differences between dialects are marked in so many ways including both vowels and consonants. There is no "primary" difference. That question is as unanswerable as the question "What is the primary sound in languages? Vowels or consonants?".

Answer 2

I must agree with Steven Xu, "primary difference" is the wrong question to ask. In addition to Steven's list, dialects also differ in:

• Word order
• Stress and rhythm (Jamaican English IIRC is syllable-timed)
• Intonation (does sentences go up or down at the end, up or down to mark a question, is the intonation pattern before the focused word equal or different to the pattern after the focused word and what the intonation is on the focused word itself). This is one of the most obvious ones in my L1, Norwegian.
• Number of cases
• Vocabulary
• etc.

There are as many dialectal differences as there are differences between languages and generally a more interesting and unanswered question is: where is the cutoff between dialect and language. The old joke that "A language is a dialect with an army and a navy" doesn't hold since German German and Austrian German aren't considered two different languages, and there's a movement underway to reunite Brazilian Portuguese and European Portuguese (makes for a bigger market, that.)