A couple of my students have asked me where they can find a reference to the Japanese terms we use in Aikido. These include not only the names of the techniques but also the Japanese expressions we use when asking someone to practise with us or thanking them after practising. Not all Aikido clubs use Japanese terms at the start and end of practice. However, at the Hartland (North Devon) dojo, we do.
At the start of practice we say Onegaishimasu (お願いします) which is a polite term of request that can be translated, approximately, as 'please'. At the end of practice, we say, Domo arigatou gozaimashita (どうもありがとうございました) which means 'Thank you very much' and, being in the past tense, is used at the end of practice only.
If you want to work on your pronunciation, I recommend the excellent AikiWeb guide to Aikido Japanese. This includes short audio files so you can hear the words spoken: http://www.aikiweb.com/language/audio.html
If you want to take your Japanese studies even further, there are lots of free resources on the Internet. For a gentle introduction to basic spoken and written (hiragana) Japanese, I'd suggest the video series Irasshai from Georgia Public Broadcasting.