I have been lecturing in five languages: Japanese, Hebrew, English, Yiddish and Esperanto. When I lecture in classroom settings, I only prepare handouts and speak spontaneously in all of them. But when it comes to talks in more formal settings with more rigit time frame such as academic conferences, I almost always prepare written manuscripts in English, Yiddish and Esperanto, usually in Hebrew, but never in Japanese. This difference reflects my different masteries of these languages. Since I have never spent a sufficiently long period of time, speaking English, Yiddish or Esperanto in academic settings, I cannot allow myself to rely on my knowledge of these languages when I have to squeeze what I would like to say into twenty to thirty minutes in academic conferences, so I do not have the luxury of stopping to look for appropriate words and expressions.
It is clear that the ideal would be to prepare written manuscripts in advance, remember them by heart by repeating them alone and lecture without them as if you were speaking spontaneously. Unfortunately, however, I do not have enough time to do this. Then I have two alternatives: either to prepare written manuscripts of lectures or to prepare only handouts and speak spontaneously on the spot. Until quite recently I tended to opt for the first alternative, but I have come to notice more and more disadvantages. For example, when you read a written manuscript, you have less eye contact with the audience, and sound more mechanical and less lively.
So I have decided to make an experiment of giving my two forthcoming talks in Hebrew solely according to handouts without preparing written manuscripts. Since I have taught my courses in Hebrew for the past six years this way, I will hopefully be able to finish this experiment in peace. I may make some stupid mistakes, but it seems to me that I will have more things to gain than what I will lose, especially in view of the fact that the Hebrew-speaking audience expects more interaction and less formality.