Word hunters, the curious dictionary by Nick Earls and Terry Whidborne

Word hunters series. UQP, 2012. ISBN 978 0 7022 4945 7.
(Age: 11+)Recommended. Fantasy. Words. Dictionaries. Books. Historical novel. Finding a dictionary tucked into the shelves of their library, twins Lexi and Al tumble down history to locate words that are losing their place in the language. The first word hello, proves elusive as they wander from Eddison's laboratory in 1877, where the first word heard on the first telephone is hello, then to a whaling ship in the Atlantic Ocean in 1835 where they hear halloo, then to the New Forest in 1100 where they witness the murder of King William, and hear the word harrow. All is intriguing and mysterious and when the children suddenly return to the present day, Al borrows the book from the library to find out what is going on. The pair sketch what they remember of the places they have been, and their father is shocked at the drawings, reminding him of those his father did. But he disappeared thirty years before, so the twins, seeing a connection between them and their unknown grandfather, resolve to find what happened to him. They ready themselves to travel once again, this time with better preparation.
Each place they find themselves in gives them a change of clothes and the keys Al carries tells them the date and place they have landed, as well as providing a key to the portal which they need to search for. Their quick survey of the setting gives an amount of historical detail to the reader which will involve them in what is about to happen. I found myself reaching for history books to corroborate the situations given, just as Al does when he gets home.
This is an engrossing time travel tale, taking modern readers to places outside what they have learnt, but nevertheless giving a substance to the story that will readily hold their interest. This is the first of a series.
Fran Knight