This paper presents Icelandic norms for the widely used pictorial stimuli of Snodgrass and Vanderwart (1980). Norms are presented for name agreement, familiarity, imageability, rated and objective age-of-acquisition (AoA) of vocabulary, and word frequency. The ratings were collected from 103 adult participants while the objective AoA values were collected from 279 children, 2.5-11 years of age. The present norms are in many respects similar to those already collected for other language groups indicating that the stimuli will be useful for further psychological studies in Iceland. The rated AoA values show a high correlation with objective AoA (r = 0.718) thus confirming previous studies conducted with English speaking participants that rated AoA is a relatively valid measure of objective AoA. However, word frequency and familiarity are more closely correlated with rated AoA than with objective AoA indicating that these factors play some role in the ratings. Objective AoA norms are therefore to be preferred in studies of cognitive processes.

The temporal structure of speech has been shown to be highly variable. Speaking rate, stress, and other factors influence the duration of individual speech sounds. The highly elastic nature of speech would seem to pose a problem for the listener, especially with respect to the perception of temporal speech cues such as voice-onset time (VOT) and quantity: How does the listener disentangle those temporal changes whicqh are linguistically significant from those which are extrinsic to the linguistic message? This paper reports data on the behavior of two Icelandic speech cues at different speaking rates. The results show that manipulations of rate have the effect of slightly blurring the distinction between unaspirated and aspirated stops. Despite great changes in the absolute durations of vowels and consonants, the two categories of syllables-V:C and VC:-are nonetheless kept totally distinct. In two perceptual experiments, it is shown that while the ratio of vowel to rhyme duration is the primary cue to quantity and remains invariant at different rates, no such ratio can be defmed for VOT. These results imply that quantity is the only one of these two speech cues that is selfnormalizing for rate. Models of rate-dependent speech processing need to address this difference. 291Many speech cues are primarily temporal in nature, being defined either by the temporal relationships between acoustic events or by the duration of individual segments (Lehiste, 1970;Lisker, 1974). A noticeable feature of normal speech is the highly variable utterance rate. The fact that listeners do not appear to be overly bothered by such speaking-rate variations poses a challenge for perceptual theory, not least concerning the perception of temporal speech cues. How is the listener able to disentangle those temporal aspects which properly are extrinsic to the phonemic message (i.e., changes of tempo) from those which define the relevant phonemic contrasts, given that both are carried simultaneously in the speech stream?Numerous studies have shown convincingly that ratedependent speech processing does in fact occur and is found to affect numerous speech cues. Miller and Liberman (1979) found that with a longer overall duration of the syllable, listeners required longer formant transition durations to hear /wa/ than to hear /ba/. Summerfield (1981) found that the longer the following vowel, the longer the voice-onset times (VOTs) that were needed

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Numerous studies, both in speech production and perception, have found that the acoustic representation of speech segments is heavily context-dependent. In particular the durations of speech sounds do not have fixed values but vary depending on their immediate context, speech tempo etc. In spite of this variability, the perceiver usually perceives correctly what the speaker intended to say. Two theoretical accounts have been given of this fact. On the one hand it has been postulated that the listener perceives correctly by taking into account the context of the speech segment he hears (the theory of normalization). Another view is that speech sound variability is primarily a surface phenomenon, and that invariants can be found in the speech wave on a closer analysis (the theory of constancy). The present study investigates the merits of these theories in the context of Icelandic speech perception. The experimental results show that normalization plays only a minor role in the perception of quantity in Icelandic.

Numerous studies have found that word frequency has a significant effect on the time it takes to name an object or read a word. Recently, claims have been made that this frequency effect is perhaps more correctly interpreted as an age of acquisition effect. This paper reports an experiment in which naming times in Icelandic for 175 stimuli from the Snodgrass and Vanderwart picture set were determined. A multiple regression analysis of naming times against a number of independent factors showed that objective age of acquisition was the strongest predictor of naming time, with familiarity and name agreement also showing a significant effect. The effect of word frequency was, however, not significant. Possible reasons for this are discussed.