A succinct explanation of the inseparable bond between reading and spelling processes which she called the amalgamation theory was given by Ehri. She argued that spellers need to know and use a combination of 'phonological, morphological, orthographic, semantic and syntactic skills'. Reading and spelling are interconnected 'like circuits on a switchboard'. Dyslexia is associated with a host of difficulties which involve reading, writing, spelling and language as well as problems with symbolic information, memory and sequencing speed of processing, such as when undertaking arithmetic or music. Dictated sentences provide an even better diagnostic test measure than individual dictated words because many other essential sub skills such as sequencing, grammatical knowledge, punctuation and working memory are simultaneously involved. Observation of a mixed ability group of pupils in a mainstream classroom will usually provide evidence of the various strategies individuals use.