Chapter 6 of the book: “MUSIC NOTATION AND TERMINOLOGY” by Karl W. Gehrkens:
64. Embellishments (or graces) (Fr. agréments) are ornamental tones, either represented in full in the score or indicated by certain signs. The following are the embellishments most commonly found: Trill (or shake), mordent, inverted mordent (or prall trill), turn (gruppetto), inverted turn, appoggiatura and acciaccatura.
Usage varies greatly in the interpretation of the signs representing these embellishments and it is impossible to give examples of all the different forms. The following definitions represent therefore only the most commonly found examples and the most generally accepted interpretations.
65. The trill (or shake) consists of the rapid alternation of two tones to the full value of the printed note. The lower of these two tones is represented by the printed note, while the upper one is the next higher tone in the diatonic scale of the key in which the composition is written. The interval between the two tones may therefore be either a half-step or a whole-step.
Whether the trill is to begin with the principal tone (represented by the printed note) or with the one above is a matter of some dispute among theorists and performers, but it may safely be said that the majority of modern writers on the subject would have it begin on the principal tone rather than on the tone above. Fig. 40.
When the principal note is preceded by a small note on the degree above, it is of course understood that the trill begins on the tone above. Fig. 41.
The trill is indicated by the sign .
The above examples would be termed perfect trills because they close with a turn. By inference, an imperfect trill is one closing without a turn.
66. The mordent consists of three tones; first the one represented by the printed note; second the one next below it in the diatonic scale; third the one represented by the printed note again.
67. The double (or long) mordent has five tones (sometimes seven) instead of three, the first two of the three tones of the regular mordent being repeated once or more. (See Fig. 43.)
In the case of both mordent and double-mordent the tones are sounded as quickly as possible, the time taken by the embellishment being subtracted from the value of the principal note as printed.
68. The inverted mordent (note the absence of the vertical line) is like the mordent except that the tone below is replaced by the tone above in each case. This ornament is sometimes called a “transient shake” because it is really only a part of the more elaborate grace called “trill.” (See Fig. 44.)[Pg 24]
The confusion at present attending the interpretation of the last two embellishments described, might be largely obviated if the suggestion of a recent writer to call the one the upward mordent, and the other the downward mordent were to be universally adopted.
69. The turn consists of four tones; first, the diatonic scale-tone above the principal tone; second, the principal tone itself; third, the tone below the principal tone; and fourth, the principal tone again.
When the sign ( or ) occurs over a note of small value in rapid tempo (Fig. 45) the turn consists of four tones of equal value; but if it occurs over a note of greater value, or in a slow tempo, the tones are usually played quickly (like the mordent), and the fourth tone is then held until the time-value of the note has expired. (Fig. 46.)
70. When the turn-sign is placed a little to the right of the note the principal tone is sounded first and held to almost its full time-value, then the turn is played just before the next tone of the melody. In this case the four tones are of equal length as in the first example. (See Fig. 47.)
The student should note the difference between these two effects; in the case of a turn over the note the turn comes at the beginning, but in the case of the sign after the note the turn comes at the very end. But in both cases the time taken by the embel[Pg 25]lishment is taken from the time-value of the principal note. For further details see Grove’s Dictionary of Music and Musicians, Vol. V, p. 184. Also Elson, op. cit. p. 274.
71. Sometimes an accidental occurs with the turn, and in this case when written above the sign it refers to the highest tone of the turn, but when written below, to the lowest (Fig. 48).
72. In the inverted turn the order of tones is reversed, the lowest one coming first, the principal tone next, the highest tone third, and the principal tone again, last.
73. The appoggiatura (lit. leaning note) consists of an ornamental tone introduced before a tone of a melody, thus delaying the melody tone until the ornamental tone has been heard. The time taken for this ornamental tone is taken from that of the melody tone.
The appoggiatura was formerly classified into long appoggiatura and short appoggiatura, but modern writers seem to consider the term “short appoggiatura” to be synonymous with acciaccatura, and to avoid confusion the word acciaccatura will be used in this sense, and defined under its own heading.
74. Three rules for the interpretation of the appoggiatura are commonly cited, viz.:
(1) When it is possible to divide the principal tone into halves, then the appoggiatura receives one-half the value of the printed note. (Fig. 50.)[Pg 26]
(2) When the principal note is dotted (division into halves being therefore not possible), the appoggiatura receives two-thirds of the value. (Fig. 51.)
(3) When the principal note is tied to a note of smaller denomination the appoggiatura receives the value of the first of the two notes. (Fig. 52.)
75. The acciaccatura (or short appoggiatura) is written like the appoggiatura except that it has a light stroke across its stem. It has no definite duration-value, but is sounded as quickly as possible, taking its time from that of the principal tone. The appoggiatura is always accented, but the acciaccatura never is, the stress always falling on the melody tone. (See Grove, op. cit. Vol. I, p. 96.)
The use of embellishments is on the wane, and the student of to-day needs the above information only to aid him in the interpretation of music written in previous centuries. In the early days of instrumental music it was necessary to introduce graces of all sorts because the instruments in use were not capable of sustaining tone for any length of time; but with the advent of the modern piano with its comparatively great sustaining power, and also with the advent in vocal music of a new style of singing (German Lieder singing as contrasted with Italian coloratura singing), ornamental tones were used less and less, and when found now are usually written out in full in the score instead of being indicated by signs.