# Analysis of Phonetic Segments of Oesophageal Speech in People Following Total Laryngectomy
## 3 Results  
The study included people who had had total laryngectomy surgery. The purpose of the research was to define feature vectors extracted from the time and frequency domains. Two analytical approaches and a number of descriptors were used to parameterize the analyzed phonetic segments. The following speech-signal descriptors used:  
* Zero-crossing rate (\(ZCR\));
* Short-time energy (\(STE\));
* Signal mean value (\(SMV\));
* The root mean square (\(RMS\));
* Local minimum and maximum;
* Spectral centroid (\(SC\));
* Irregularity of spectrum (Ir);
* Cepstrum;
* _MFCC_--mel-frequency cepstral coefficient. In the first analytical approach, the values of the \(ZCR\), \(STE\), \(SMV\) and \(RMS\) features were calculated over the length of the entire phonetic segment. The distribution of the values of the features was estimated on the basis of their minimum value, maximum value, mean value, and standard deviation. Below, the distribution values of the discussed features from the phonetic segments of the word \",barrel\" (in Polish \"beczka\" in Polish, \"beczka\"), have been presented (Tables 2-4). \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **ZCR** & **STE** & **SMV** & **RMS** \\ \hline \multicolumn{5}{c}{**Laryngeal persons**} \\ \hline average & 789.33 & 284.26 & 0.026 & 0.156 \\ min & 383.00 & 121.42 & 0.010 & 0.102 \\ max & 1217.00 & 625.81 & 0.043 & 0.207 \\ SD & 303.23 & 186.58 & 0.013 & 0.043 \\ \hline \multicolumn{5}{c}{**Health persons**} \\ \hline average & 339.25 & 766.80 & 0.073 & 0.268 \\ min & 306.00 & 571.78 & 0.053 & 0.231 \\ max & 378.00 & 983.39 & 0.095 & 0.309 \\ SD & 38.13 & 225.05 & 0.019 & 0.036 \\ \hline \end{tabular} SD—standard deviation.  
\end{table} 
Table 4: The distribution of the values of the features: the third phonetic segments  �_xa”—the word “beczka”. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **ZCR** & **STE** & **SMV** & **RMS** \\ \hline \multicolumn{5}{c}{**Health persons**} \\ \hline average & 209.75 & 606.79 & 0.083 & 0.286 \\ min & 80.00 & 374.83 & 0.064 & 0.252 \\ max & 269.00 & 854.15 & 0.107 & 0.327 \\ SD & 87.37 & 209.28 & 0.018 & 0.031 \\ \hline \end{tabular} SD—standard deviation.  
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **ZCR** & **STE** & **SMV** & **RMS** \\ \hline \multicolumn{5}{c}{**Laryngeal persons**} \\ \hline average & 543.67 & 152.25 & 0.039 & 0.187 \\ min & 214.00 & 37.93 & 0.012 & 0.110 \\ max & 916.00 & 398.20 & 0.078 & 0.280 \\ SD & 274.73 & 128.06 & 0.028 & 0.071 \\ \hline \multicolumn{5}{c}{**Health persons**} \\ \hline average & 464.50 & 384.22 & 0.128 & 0.322 \\ min & 148.00 & 108.09 & 0.045 & 0.211 \\ max & 1311.00 & 908.49 & 0.350 & 0.591 \\ SD & 564.95 & 376.96 & 0.148 & 0.181 \\ \hline \end{tabular} SD—standard deviation.  
\end{table} 
Table 3: The distribution of the values of the features: the second phonetic segments �_cz”—the word “beczka”. Error matrices (also called confusion matrix) should be interpreted as:  
1. Markings \"a\" and \"b\" as a group of examined people (laryngeal and healthy);
2. Shaded cells in the table contain the correct classification. For example, in Table 5, in1 st row, 93.75% means the correct classification of samples from laryngectomised people, and 6.25% means incorrect classification. It should be noted that in this case, the laryngectomized people were recognized with 100% accuracy--with 75% accuracy in the recognize of healthy people. Due to the adopted procedure for analyzing the frequency domain of phonetic segments (described in point Section 2.4 \"Frequency Domain Descriptors\"), the features of Ir and Br (computed for each spectrum of this matrix) were obtained from the spectral matrix for a single signal and then their average value was calculated. This means that Ir and Br for a specific phonetic segment is the average of the values of these features obtained from the obtained spectrums (an example spectrum matrix is shown in Figure 6).