Age of acquisition and imageability norms for base and morphologically complex words in English and in Spanish.

The extent to which processing words involves breaking them down into smaller units or morphemes or is the result of an interactive activation of other units, such as meanings, letters, and sounds (e.g., dis-agree-ment vs. disagreement), is currently under debate. Disentangling morphology from phonology and semantics is often a methodological challenge, because orthogonal manipulations are difficult to achieve (e.g., semantically unrelated words are often phonologically related: casual-casualty and, vice versa, sign-signal). The present norms provide a morphological classification of 3,263 suffixed derived words from two widely spoken languages: English (2,204 words) and Spanish (1,059 words). Morphologically complex words were sorted into four categories according to the nature of their relationship with the base word: phonologically transparent (friend-friendly), phonologically opaque (child-children), semantically transparent (habit-habitual), and semantically opaque (event-eventual). In addition, ratings were gathered for age of acquisition, imageability, and semantic distance (i.e., the extent to which the meaning of the complex derived form could be drawn from the meaning of its base constituents). The norms were completed by adding values for word frequency; word length in number of phonemes, letters, and syllables; lexical similarity, as measured by the number of neighbors; and morphological family size. A series of comparative analyses from the collated ratings for the base and derived words were also carried out. The results are discussed in relation to recent findings.