Eulogies
The term eulogy comes from the Greek meaning, quite simply "good words". At a funeral, a eulogy is a speech made in praise of the departed.
Do we have to have one?
No. There is absolutely no obligation. But a eulogy does help to focus the mourners on the life and merits of the deceased. It offers a moment to draw thoughts on the life that has been led, and the person who they are gathered to say farewell to.
What should we say?
Anything you like. The speaker can simply say how much the deceased meant to them.
Alternatively, this is an opportunity to recount something about the deceased's life – a brief biography. The mourners may well have known the deceased only during one segment of his or her life, or from one angle (in the workplace, or as a distant family member, for instance), so it can be rewarding for all to hear something of the broader picture.
A eulogy should be, above all, positive. Any memories that might be awkward, embarrassing or painful should be avoided – or if unavoidable, mentioned with extreme delicacy.
Who should give the eulogy?
Eulogies are usually given by a close family member or friend.
Note that, at a funeral of a loved one, this can be extremely hard, emotionally. Mourners are very forgiving if someone making a speech shows his or her emotions – but if the speaker breaks down completely, this can be embarrassing for all concerned.
So choose someone who feels up to the task. Alternatively, you can write a eulogy and ask the priest or officiant to read it on your behalf.