The phonology of second languages is different from the phonology of first languages in various ways. The differences are considered to come from general characteristics of second languages, such as slower speech rate, lower proficiency than native speakers, and from the interaction between non-native speakers' first and second languages.
Research on second-language phonology has been done not only on segments, but also on prosody. Second-language prosody, like second-language segments, has been studied in terms of both its global characteristics and the interactions between first languages and second languages.
First language to second language
Global second-language prosody characteristics
Speech rate
L2 speech rate is typically slower than native speech. For example, Mandarin Chinese speakers’ speech rate in an English utterance is slower than native English speakers’ speech rate (Derwing and Munro, 1995), and speech rates in a sentence by highly experienced Italian and Korean nonnative speakers of English are slower than that of native English speakers' (Guion et al., 2000). In this study, the main factor of the slower speech rate for the Italian and Korean accented English was the durations of the vowels and sonorant consonants (Guion et al., 2000). Another source of the slower speech rate in L2 speech is that L2 speakers tend to not reduce function words, such as "the" or "and," as much as native speakers (Aoyama and Guion, 2007). The generally slower speech rate in L2 speech is correlated with the degree of perceived foreign accent by native listeners (Derwing and Munro, 1997).
Interaction between first- and second-language prosody
L2 speech is influenced by the speaker's L1 background. Such influences have been explored in relation to many prosodic features, such as pitch perception and pitch excursion (Beckman, 1986; Aoyama and Guion, 2007), stress placement (Archibald, 1995, 1998a, 1998b; Flege and Bohn, 1989; Archibald, 1997), syllable structure (Broselow and Park, 1995; Broslow, 1988; Eckman, 1991), and tone (Sereno and Wang, 2007; Guion and Pederson, 2007).
Pitch perception and pitch excursions
When perceiving accented syllables in English, Japanese nonnative speakers of English tend to rely only on F0, or pitch of the accented syllables, while native speakers use F0, duration, and amplitude (Beckman, 1986). This finding was confirmed in production, by showing that the excursions of F0 of English content words were larger for Japanese nonnative speakers of English than for native English speakers (Aoyama and Guion, 2007).
In both studies, the reason for this phenomenon was proposed to be related to the characteristics of the nonnative speakers’ L1, Japanese. Japanese is a mora-timed language, and because of this, longer syllable duration makes a phonological difference in Japanese. Therefore, when expressing stress in Japanese, Japanese speakers may rely more on F0 than duration, which is a critical cue for a different phonological distinction. This L1 characteristic might interfere with Japanese speakers’ perception and production of English, which is a stress-timed language and might be free of such durational restrictions.
Stress placement on words
Influence from L1 to L2 was also found in stress placement on words. Hungarian learners of English tend to place initial stress on English words that do not have initial stress, because Hungarian has fixed initial stress and this is transferred to Hungarian speakers' L2 English prosody (Archibald, 1995; 1998a; 1998b). Spanish speakers of English were found not to stress target stressed syllables in English, and this might be due to the lack of stress in Spanish cognates and the lexical similarity between Spanish and English words (Flege and Bohn, 1989). In addition, it is suggested that speakers of tone languages (e.g., Chinese) and pitch-accent languages (e.g., Japanese), both of which use pitch as a phonologically meaningful item, do not compute stress placement in English, but rather store the stress information lexically (Archibald, 1997).
Syllable structure
L2 speakers can also perceive some innate characteristics of the L2, which lead to different repair strategies for different phonological patterns. Korean L2 speakers of English add an extra final vowel to some English words but not to all (Broslow and Park, 1995), as in (1).