Екі жақын нотаның жылдам тікелей алмасуы

Rapid alternation between two adjacent notes
the consonantal sound

The trill (or shake, as it was known from the 16th until the early 20th century) is a musical ornament consisting of a rapid alternation between two adjacent notes, usually a semitone or tone apart, which can be identified with the context of the trill (compare mordent and tremolo). It is sometimes referred to by the German Triller, the Italian trillo, the French trille or the Spanish trino. A cadential trill is a trill associated with each cadence. A trill provides rhythmic interest, melodic interest, and—through dissonance—harmonic interest. Sometimes it is expected that the trill will end with a turn (by sounding the note below rather than the note above the principal note, immediately before the last sounding of the principal note), or some other variation. Such variations are often marked with a few appoggiaturas following the note bearing the trill indication.

quote|The taste for cadences (like the taste for sequences), and with them the obligation to bring in their implied cadential trills, was ingrained in baroque musicianship For those who do not like cadences, sequences, and cadential trills, baroque music is not the scene.|Robert Donington, Baroque Music, Style and Performance In the baroque period, a number of signs indicating specific patterns with which a trill should be begun or ended were used. In the Klavierbüchlein für Wilhelm Friedemann Bach, Johann Sebastian Bach lists a number of these signs together with the correct way to interpret them. Unless one of these specific signs is indicated, the details of how to play the trill are up to the performer. In general, however, trills in this era are executed beginning on the auxiliary note, before the written note, often producing the effect of a harmonic suspension which resolves to the principal note. But, if the note preceding the ornamented note is itself one scale degree above the principal note, then the dissonant note has already been stated, and the trill typically starts on the principal note. Several trill symbols and techniques common in the Baroque and early Classical era have fallen entirely out of use, including for instance the brief Pralltriller, represented by a very brief wavy line, referred to by Carl Philipp Emanuel Bach in his Essay on the True Art of Playing Keyboard Instruments (Versuch) (1753–1762). Beyond the baroque era, specific signs for ornamentation are very rare. Continuing through the time of Mozart, the default expectations for the interpretation of trills continued to be similar to those of the baroque. In music after the time of Mozart, the trill usually begins on the principal note. All of these are only rules of thumb, and, together with the overall rate of the trill and whether that rate is constant or variable, can only be determined by considering the context in which the trill appears, and is usually to a large degree a matter of opinion with no single "right" way of executing the ornament.

The trill is frequently found in classical music for all instruments, although it is more easily executed on some than others. For example, while it is relatively easy to produce a trill on the flute, the proper execution on brass instruments requires higher skill and is produced by quickly alternating partials. While playing a trill on the piano the pianist may find that it becomes increasingly difficult to execute a trill including the weak fingers of the hand (3, 4 and 5), with a trill consisting of 4 and 5 being the hardest. On the guitar, a trill can be either a series of hammer ons and pull offs (generally executed using just the fingers of the fretting hand, but players can use both hands), or a rapidly plucked pair of notes on adjacent strings, known as a cross string trill. Trill keys are used to rapidly alternate between a note and an adjacent note often in another register on woodwind instruments. On the bowed instruments, the violin and the viola in particular, the trill is relatively easy to execute, with a straightforward bowing and the trill involving the oscillation of just one finger against the main note which is stopped by the finger behind, or more rarely, the open string.

Trills may be performed on valveless brass instruments by rapidly slurring between two adjacent notes by means of the embouchure – this is colloquially known as a "lip trill." This was a common practice on the natural trumpets and natural horns of the Baroque/Classical era. However the lip trill is often still used in the modern French horn in places where the harmonics are only a tone apart (though this can be difficult for inexperienced players). Such trills are also a stylistic feature of jazz music, particularly in trumpet parts.

Vocal music of the classical tradition has included a variety of ornaments known as trills since the time of Giulio Caccini. In the preface to his Le nuove musiche, he describes both the "shake" (what is commonly known today as the trill) and the "trill" (now often called a Baroque or Monteverdi trill). However, by the time of the Italian bel canto composers such as Rossini, Donizetti and Bellini, the rapid alternation between two notes that Caccini describes as a shake was known as a trill and was preferred. Coloratura singers, particularly the high voiced sopranos and tenors, are frequently required to trill not only in the works of these composers but in much of their repertoire. Soprano Dame Joan Sutherland was particularly famed for the evenness and rapidity of her trill, and stated in interview that she "never really had to learn how to trill". The trill is usually a feature of an ornamented solo line, but choral or chorus trills do appear. Despite the trill being written in many works for voice, a singer with an even, rapid trill is a rarity. Opinion is divided as to if and how well a trill can be taught or learnt, though mezzo soprano Marilyn Horne frequently stated that she gained her trill by a commonly taught exercise, alternating between two notes, starting slowly and increasing velocity over time. The director of the Rossini Opera Festival, Alberto Zedda has opined in interview that the "widespread technical deficiency", the inability to trill, is a source of "frustration and anguish". In fact, whole performances and recordings, especially of bel canto works, have been judged based on performance—or lack thereof—of trills, especially trills written in the score as opposed to trills in a cadenza or variation.

The word trillo is sometimes used to mean the same as trill. However, in early music some refer to a related ornament specifically called trillo:

Montserrat Caballé was a known exponent of the trillo, as can be heard from her famous 1974 Norma.