Sonata and sonatina are essentially identical musical forms. The sonatina is a “little sonata,” usually shorter and easier to perform than a sonata. The word “sonata” comes from the Italian sonare, “to sound,” and originally it meant merely a “sound piece,” (a musical thought sounded on one or more instruments). In its early form it was a composition of two or three distinct, thematically related sections on the pattern of A-B, or A-B-A, as developed by the classical masters (Haydn, Mozart, and Beethoven). It became a larger, extended, and unified musical structure built on two or three contrasting themes, presented in a continuous melodic flow in related keys with connecting transitional passages. This structure, usually referred to as “sonata-allegro” form or “first movement” form, consists of three sections: Exposition, Development, and Recapitulation. The sonatina does not always contain all the components of the sonata form. In its simplest examples, it is a small three-part song form (A-B-A) with the melodies simply stated, without thematic expansions and developments. Sonata, and often sonatinas, too, usually consist of two to four independent, self-contained parts called movements. The second movement can be simple two- or three-part song form and the last movement is usually a rondo. Taken from “An Introduction to Playing Sonatinas” by Denes Agay.
Musical form in which a main theme or section alternates with one or more secondary themes, called episodes. In its simplest form, the rondo is very close to the ternary form of a A-B-A pattern. More often the rondo consists of a main theme and two episodes (pattern A-B-A-C-A).
Also called “two-part song form,” consists of two sections (two musical sentences), A and B, both of which are usually repeated.
“Rounded” Binary Form:
Occurs when the second section of the binary form concludes with a restatement of the first section in whole or in part.
“Three-part song form,” pattern A-B-A or A-B-C.
Contains the main theme, a second theme in a related key (usually the dominant), and often also a closing theme.
Contains one or more previously presented themes or theme fragments “developed” into varied new sound patterns, moving freely through new keys and leading directly into the recapitulation.
A repetition of the exposition section with all themes in the original key.