The most common use of the verb "notice" means "to see, to observe or to recognize". e.g., I noticed that the Philippinos in Mindanoa have darker complexions than the people in Baguio. e.g., I notice that you have lost weight lately. e.g., I have noticed that the weather this year is very different than last year's weather. The most common use of the verb "realized" means "to understand something or come to understand something". e.g., I realize that you have been trying to lose weight lately. e.g., If you visit Canada for one year you will realize that we do not have snow on the ground all year long. e.g., You will realize that the snow is present for only 4 or 5 months. e.g., I have realized that most Philippinos speak English. The most common use of "said" is the past tense of the verb "to say" and it means "speak/spoken". e.g., Did I say (tell you) that I have visited the Philippines before. e.g., I have said many times that the Philippino people are friendly. e.g., I have said that I have noticed that life in the Philippine is not easy, and I realize that many of the Filipinas leave their home and family to work in other countries. Suwerte...

I noticed (realized) u changed your hair style since our last meeting... But u can't say this sentence using "I said" I said to him that he changed his hair style since our last meeting...