: This paper compares formant transitions in English, French and German monophthongs after labial and lingual (tip, front and back) consonants. The monophthongs were extracted from speech samples read by female speakers. The formant values were measured in 9 points within each vowel. The line graphs representing formant transitions were plotted. The derivatives of the resulting functions at 9 points were calculated to compare the slopes of different formant trajectories. The formant values were converted from Hertz to Bark scale in order to evaluate the formant structure variability. F2 values were the highest in German vowels and the lowest in English monophthongs. However, English vowels demonstrated the highest F1 values. Differences in the steepness of the first transition region were observed in French rounded and unrounded monophthongs. The region in which the greatest slope occurred was the same for English and German monophthongs, but different for French vowels. The highest variability of formant structure was observed in F1 of English vowels. Overall, the formant structure of German vowels was the least variable. In English and German, formant structure variability was lower in the back
monophthongs compared to the front vowels. However, French monophthongs showed the
opposite tendency