Derailleur gears operates the lever while pedalling, the change in cable tension moves the chain-guide from side to side, "derailing" the chain onto different sprockets. For more information about the choice of particular gear ratios and sprocket sizes, see Bicycle gearing. "Derailleur" is a French word, spelled "dérailleur" in French, derived from the derailment of a train from its tracks. Its first recorded use was 1930. At least one notable bicycle industry author has attempted to promote the anglicized spelling of "derailer". As of 2013, however, neither Merriam-Webster nor the Oxford English Dictionary has an entry for "derailer". Various derailleur systems were
Word sort be introduced at a very early stage and develop with a child’s individual ability. Sorting pictures or oral vocabulary is a manipulation of sounds, and this manipulation increases awareness. A simple introductory sort is by initial sound and this can develop to ending sound, vowel sounds, and word families sorts. The root of importance is student motivation and involvement in the sort. By “setting the scene with sounds," sorts may include concrete materials and pictures linked to learner interest. Phonemic awareness, not phonics, is the understanding that our spoken sounds work together to make words. This is a very early