Available at

4.1.1 Delivery rate 
The delivery rate, also called speech rate, is measured as the number of words 
per minute (Plevoets & Defrancq, 2018). It is an important factor to establish 
intelligibility and clarity (Rodero, 2012). Here are some examples of average 
speech rates: a comfortable presentation has a rate between 100 and 150 words 
per minute (w/m) while radio hosts utter between 150 and 160 w/m and sports 
commentators between 250 and 400 w/m. As for interpreting, interpreters think 
that a delivery rate between 100 and 120 English w/m is optimal for speeches that 
are not read out from a written text (Li, 2010). However, this figure can change 
according to the speech type. Here is the comment from the message board of the 
International Association of Conference Interpreters (AIIC): 
We all know that a speaker speaking at about 100 to 120 words per minute is 
perfectly acceptable. However, there are exceptions to this: dense originals without 
much redundancy. Such speeches may seem excessively fast even if presented at 
120 words per minute. Normally, however, any original exceeding 140 words per 
minute is fast. I have clocked speakers at 180 words per minute (Communicate 
1999). 
Generally speaking, the delivery rate is considered as slow if it is lower than 130 
w/m, average between 130 and 160 w/m and fast over 160 w/m. Studies show that 
the delivery rate has a direct influence on interpreting quality, and accuracy 
decreases as the speech gets faster. In Gerver’s study (1971), we see that the 
number of incorrectly translated words is caused by an increased delivery rate. 
Galli (1990) states that speech rate correlates with an increased number of 
omissions and mistakes, whereas Chernov (2004) says that the interpreter’s 
delivery rate does not increase proportionally with the speaker’s.

---

Results and discussion 
 
page 57 
Table 8 – Overview of IN delivery rates 
Source text 
Number of words 
Duration 
Delivery rate
(in words/minute) 
IN01 
1,378 
0’28”-14’32” = 
14’04” 
97.96 w/m 
IN02 
1,343 
0’05”-13’42” = 
13’37” 
98.63 w/m 
IN03 
1,487 
0’00”-13’45” = 
13’45” 
108.14 w/m 
IN04 
1,414 
0’36”-13’28” = 
12’52” 
109.9 w/m 
IN average 
1,405.5 
13’34” 
103.66 w/m 
Table 8 displays the total number of words, duration and delivery rate of each 
source speech included in the corpus. All source speeches were read out by the 
same lecturer under the same conditions. As can be seen in Table 8, the delivery 
rate is slow for all IN (less than 130 words per minute). Interestingly, the delivery 
rate of each IN is higher than the preceding one. It is important to remember that 
the first IN was used on November 3
rd
, the second on November 10
th
, the third on 
November 17
th
and the last one on December 8
th
, 2016. I can thus conclude that 
the lecturer gradually increased her delivery rate (whether consciously or 
unconsciously), thereby increasing the difficulty of the interpreting tasks to be 
performed by the students.

---

Results and discussion 
 
page 58 
Table 9 – Overview of STU delivery rates 
IN01