By the time someone gets to celebrate their 70th birthday, you have probably known them for very many years therefore you need to be personable. Make sure you mention the relationship that you have with the person.

Say something about where the person celebrating the birthday was born and make a comparison about his physical features in the past and present.  At seventy, the person has been in retirement for a while therefore you should mention the career he was involved in and how dedicated he was to his work. Include his personal attributes that make him stand out from everyone else like his charm and good sense of fashion.

Make fun about some of the words that the person likes to use to cause a little embarrassment but make sure you do not cross the line with the jokes. Mention some of the interests and hobbies that the person has and the places they have gone to enjoy them. If the person is an art lover you can name some of the art galleries that they like visiting every now and then.
The children and grandchildren that the person has should also be included in the 70th birthday speech.