Word order in English is of generally greater importance than it is in Latin. Many Latin sentences could have their meaning unchanged no matter how the words were jumbled around, whereas most English sentences (and even phrases) change or lose meaning if the word order is altered. However, not ALL of English is slavishly dependent upon word order. I have to disagree with Peter T. His point about word order is generally true of the language as a whole but is not applicable as the final word on placement of prepositions. Is there really anyone here who does not understand, "That's a toy I used to play with?" Is there any improvement in saying "That's a toy with which I used to play?" I think not.

I think you'll find, Murray, that the proscription of split infinitives is also based on obsequious deference to Latin grammar. Latin infinitives are single words and thus CANNOT be split. English infinitives, being two words, lend themselves readily to splitting. Sometimes this can enhance clarity by eliminating any doubt as to which word in a sentence is modified by a particular adverb. And consider "He agreed to always call before visiting." The placement of "always" anywhere else in that sentences either changes the meaning or makes it come across as terribly stilted and awkward. There's really no good reason to disallow spit infinitives in English.