Wordle is an app that generates word clouds - it's free. The app is available in both Widows and Mac OSX versions. Simply download the app, install it, and then run it.
Here is an example of a word clouds based on a reading text.
The text example was pasted in without any modifications on my part, and you can see that the word English is by far the largest, followed by India, sector, education, Indian and now. This tells you that these words appear most frequently in the text. You could use the word cloud to ask your learners to try to predict the text, based on the size (= frequency) of the words, for example.