In ordinary fluent conversation people pronounce roughly four syllables, ten or twelve phonemes and two to three words out of their vocabulary (that can contain 10 to 100 thousand words) each second. Errors in speech production are relatively rare occurring at a rate of about once in every 900 words in spontaneous speech. Words that are commonly spoken or learned early in life or easily imagined are quicker to say than ones that are rarely said, learnt later in life, or are abstract.