## 1 Introduction
[27] examined high-variability training for Dutch Mandarin learners with Mandarin disyllabic pseudo-words. Their findings indicated that such training was effective in post-test perceptual recognition, but this was contingent on the learners' individual abilities. Specifically, increased variability hindered perceptual learning for low-ability perceivers while enhancing it for high-ability perceivers. Thus, the process of acquiring tones by L2 learners warrants careful consideration. Polish, a Slavic language, is a stress-timed language. It typically features multisylllabic words and a relatively rich consonant system, including retroflex and palatal fricatives and affricates, while its vowel system is relatively simple, comprising six oral and two nasalized vowels: \(\tilde{\mu}\), \(\varepsilon\), \(\mathrm{i}\), \(\mathrm{a}\), \(\mathrm{u}\), \(\mathrm{u}\), \(\mathrm{\beta}\), \(\tilde{\mathrm{r}}\), \(\tilde{\mathrm{\beta}}\)/. In Polish, stress predominantly falls on the penultimate syllable [29]. In contrast, Mandarin Chinese is characterized as a monosyllabic language, where the meaning of a word is determined by its lexical tone. Mandarin tones are defined by relative pitch rather than absolute pitch. Recently, ref. [20] discusses the transition of Mandarin Chinese from a predominantly monosyllabic to a disyllabic language. The primary reason for this shift is the high number of homophones in monosyllabic words, which leads to communication difficulties. According to the five-point scale proposed by [30], Mandarin tones are described as follows: high-level T1 is 55, rising T2 is 35, low or falling-rising T3 is 214, and falling T4 is 51. When Mandarin Chinese phonation pitch discussed, the tones' fundamental frequency (F0) requirements must be taken into consideration. As for Mandarin Chinese, F0 operates between 162 Hz and 352 Hz (a female) and 68 Hz and 223 Hz (a male) when pronouncing the syllable ma in four Mandarin Chinese tones [8]. The average means of F0 from another study carried out by [PERSON] 1997 [31] examining eight male speakers, run from about 90 Hz (for T3) to slightly above 140 Hz (T4). Similar results were found in [PERSON] 1981 [32], for one female) and [PERSON] ([33], for one male) with the tonal range from 45 Hz to 250 Hz (female) and 40 Hz to 157 Hz (male). In addition, ref. [34] reports that the frequency for male speakers ranges from roughly 78 to 185 Hz, and for female speakers from around 104 to 262 Hz. The range of spoken Mandarin Chinese (a tone language) is greater than that of English (a stress language) [35] and the range of females is wider than that of males. Furthermore, the tonal range of a single speaker may differ depending on which language they are speaking. Ref. [4] pointed out that the average pitch range of native Mandarin Chinese speakers is 1.5 times wider than that of native English speakers when speaking English, but the range of English speakers may increase when they switch from their English to Mandarin Chinese. (104-105 of [36]) report that most Polish words operate within the 1300-1600 Hz range for speech, with a significant range of 100-2300 Hz; Table 1 shows the details of the tonal ranges in Mandarin Chinese and Polish. On the other hand, Polish speakers reveal a significantly higher F0 register when compared to English and German speakers (pp. 1308-1310 of [37]; p. 654 of [38]), to which the sibilants contribute evidently. In the study by [37], the pitch range and variation characteristics of English, German, Bulgarian, and Polish were examined. They found that for both male and female speakers, the average pitch and pitch range (s.t.) as well as the maximum F0 used by speakers of Slavic languages (Bulgarian and Polish) were significantly higher than those of the Germanic languages (English and German), and also exhibited greater standard deviation. Similarly, ref. [38] found differences in acoustic parameters such as F0 among speakers of German, Italian, and Polish.