根据句意，用所给单词的适当形式填空。
1.There are ________ (difference) between British English and Australian English.
2.If you want to make yourself ________(understand), you should speak clearly and slowly.
3.Speech is the fastest method of _________ (communicate) between people.
4.The place of interest is visited by millions of ________(tourist).
5.With ________(who) do you often practice your English?