Slips of the tongue are a normal part of speech. It is very difficult for anyone to speak at length without stumbling over their words briefly. This is particularly true for television commentators as this Sky correspondent (Mark Stone) found out recently:
01 er but 02 Theresa May’s gotta persuade her other European counterparts 03 er that time is clicking 04 that er (.) ticking 05 er the clock is ticking for for Europe 06 it’s clicking (.) 07 TICKING for Britain as well 08 they both need to get a move on
The words ‘ticking’ and ‘clicking’ are very close semantically and phonologically so it is no surprise when this correspondent in line 03 mistakenly swapped them. A repair procedure then kicked in in line 04 where the overt speech was corrected. Unfortunately for this correspondent, once these two words had been confused in the mind it was going to be very difficult to keep them apart subsequently and so it proved when in line 06 the same slip of the tongue occurred again. The exasperated correspondent forcefully corrected himself again in line 07 before wrapping up.