Types of Speech delivery

There are for basic types of delivery 

1. extemporaneous, 
2. impromptu, 
3. manuscript, and 
4. memorises.     
1. Extemporaneous:                                                                                An Extemporaneous speech is planned in advance but presented in a direct, spontaneous manner. This type of speech are are conversational in tone. It give the audience members the impression that are talking to them directly and honestly.It have some disadvantages. It is difficult to keep exact time limits to be exact in wording or to be grammatically perfect with an extemporaneous speech.                                                              
2. Impromptu:                                                                                            An impromptu speech is spontaneous by definition but delivery style that is necessary for informal talks, group discussions, and common on others speeches.                                                    
3. Manuscript:                                                                                                                     Manuscript speeches are read word for word from a prepared text. They are necessary when you are speaking for the record as when speaking at legal proceedings or when presenting scientific findings.                                                                       
4. Memorised:                                                                                          Memorized speeches those learned by heart are the most difficult and often the least effective. They often seem excessively formal. 

Source: Page No 339-342 Public communicationUnderstanding Human communication-Tenth Indian edition, Ronald B Adler& George Rodman, Oxford University press