Abstract
Suffixation influences lexical stress in one of three ways. A suffix attached to a word root/stem may take the stress itself, or it may cause it to move from where it was in the uninflected stem to another syllable, or it may keep stress as is. Stress misassignment is very common in the speech of Arabic-speaking English as a foreign language (EFL) learners. This study was conducted to investigate how Arabic-speaking EFL learners at Prince Sattam bin Abdulaziz University (PSAU) in Saudi Arabia assign lexical stress in word roots/stems and their suffixed derivatives to find out whether stress in suffixed words presented a greater challenge to the learners than stress in the stem; the study also aimed to examine whether errors in stress assignment were caused by first language(L1) interference. 112 students from PSAU were randomly chosen to pronounce 80 suffixed words as well as their roots/stems. The pronunciations were recorded, and the recordings were analyzed by the three researchers and three raters. The study concluded that suffixed words do not present a more significant stress assignment challenge than uninflected stems, the type of syllable attached to a word is not as important as the number of syllables, syllable weight and structure in a word, and that L1 influence may be one of the causes but not the only cause of lexical stress misassignment.