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 understanding that can be developed in a variety of ways. Comparing sounds is the easiest task for developing phonemic awareness. Sound sorts can be introduced very early on and develop strategically throughout primary learning. An ability to sort sounds is essential for early reading because sound manipulation is a stepping stone to word study and decoding ability. For some students a direct instructional approach is not necessary in the development of sound study and sorting. Other children who have had less exposure or lack the understanding of sounds and their manipulability may need further instruction to develop their ability. Teachers