Not a all. As a phonetic enthusiast I can assure you Pinyin is by far the worst representing Chinese sounds with English letters. It is made to represent Chinese phonetic, but its creators are seemingly completely ignorant toward basic phonetic rules, such as voicing and aspiration, and how words actually sound in English.
As an example, b in English is called an unaspirated voiced consonant, which means you vibrate your vocal folds, but send only a little breath when you sound it. You can compare it with p, its aspirated voiceless counterpart, for which you do not vibrate the vocal folds (voiceless), but sends a strong breath through your month (aspirated). Chinese does not have most voiced consonants present in English, so Pinyin naively uses b (also d and some others) to represent voiceless aspirated consonants, which does not sound like a b, but more like p in “spade”. This results in most of the foreigners learning Chinese with Pinyin bringing English pronunciation when they speak, and makes them sound way too stiff and thus awkward.
Wade-Giles, in comparison, is much more systematic, and does a much better job hinting speakers with European (especially Germanic language) background to sound more correctly. Bopomofo does not have this problem, as it basically invents a new set of scripts. Pinyin probably lets you pick up casual speaking Chinese most quickly, but beyond that, it’s a curse.
[Edit]: Voice “folds” not cords, sorry. Also fixed some typos.
Pinyin is very well-adapted for (Mandarin) Chinese. It isn't specifically designed for English learners, but if you understand phonetics and learn the sounds first, that shouldn't matter. The alphabet is originally from Latin and is used in a variety of ways in different languages, e.g. Turkish c sounds like English j, German j sounds like English y, so the foreign accent problem exists generally.
There are two bilabial stop consonants, called p and b, in many different languages, with different sounds, e.g.
Mandarin English French
unaspirated voiced - b b
aspirated voiced - - -
unaspirated unvoiced b - p
aspirated unvoiced p p -
though there is, as you point out, an unaspirated unvoiced allophone of p in "spade". Other stops (t, d, k, g) follow a similar pattern.
English speakers using English p and b in Mandarin will still be understood even if their b sounds foreign, but French speakers might not be, because French p sounds like a Mandarin b.
The only change I'd like is replacing Pinyin -ong with -ung.
I think it would also help to expand -iu to -iou and -ui to -uei, and of course u->ü where applicable. IMEs could still accept both forms.
Pinyin is pretty well-adapted for entering Chinese, but I think that goal is at odds with being easy to pronounce. I'm not sure that having one ISO standard for both purposes is a good idea, although if China ever starts to export more culture, maybe everyone will eventually learn how to pronounce Hanyu Pinyin.
Choosing aspirated unvoiced consonants as "typical" of English is very weird. Native English speakers do not consciously distinguish aspiration but they do distinguish voicedness so it seems it would be more accurate to call the aspirated form the allophone (aspiration only occurs at the beginning of words and stressed syllables, and never after "s" as you point out, so the unaspirated form probably occurs more frequently too).
Still, I agree with your main point. The Latin alphabet is not used like the IPA by most languages, even English has not preserved all the original Latin sounds as used by the Romans. And there's even precedent for some of the sound choices made in Pinyin that would seem completely alien to English speakers. For example "c" is used in all the Slavic Latin alphabets (e.g. Polish, Czech, etc) for the unaspirated version of the Pinyin "c" sound. German and Pinyin use the letter "z" for the same sound, etc.
When I was taught Pinyin, the instructor explained that the phonetics were influenced by the Russian pronunciation of the roman alphabet. Not sure if this is true, or if it explains the issues you're describing. But it seemed plausible that China thought they were going to be closer to the USSR given the shared ideology in the 50's.
In any case, as a person who has a decent pronunciation in Chinese but lacking the ability to fully read/write, Pinyin has been absolutely great for being able to type Chinese informally. I can communicate almost anything I can say, and that's truly wonderful. Part of that is the smart prediction software. But Pinyin has a big part in it too: it's not difficult at all to sound out a word and figure out how to spell it in Pinyin. That's the essential feature that Chinese characters lack, and Pinyin nails that essential quality as far as I can tell.
I know very little Russian and can’t say for certain, but I think Russian is similar to English in these consonants.
I should make it clear I don’t think Pinyin is a bad system, only that it does not map sounds to European languages well. And that is fine, as least for its original purpose. Contrary to common belief, Pinyin was not developed to better educate illiterate people (this does not even make sense if you think carefully), but as the next step after letter simplification (what we know as Simplified Chinese today) towards Chinese Romanisation. The goal was not to represent sounds of Chinese characters, but to outright replace them. The actual reason behind using (for example) b and p instead of p and p' is exactly this—they are optimising for ease to write, not sound accuracy.
And in regard to making it easy for people not prolific with Chinese letters to read, be them foreigners or simply illiterate, a phonetic transcription system is indeed important. But although having a standard phonetic transcription is key to the jump in literacy in China, I would argue the same can be achieved with any decent system, and a few of them are already around by the time they started working on Pinyin.
All in all, while Pinyin is good for its original purpose, it achieved its current status not because of academical reasons, but political ones. The Chinese Communists government had always have a habit ignoring existing systems and inventing their own. :p
Definitely not. Russian has no aspirated consonants at all, nor would they pronounce them in the Latin alphabet. In fact a Russian would pronounce the roman "T" exactly the same way a Mandarin speaker would pronounce the pinyin "D" so I don't think there's much credence to your instructor's story.
I don't think pinyin was even meant to represent voicing and aspiration in a way that is similar to English or otehr Germanic languages. There are many other languages using Latin alphabet which are a little bit different with both consonants and vowels, and that doesn't stop from sharing the letters.
Pinyin does a good job in providing a fairly consistent way to present Chinese sounds using Latin alphabet. It's also the workable way to input Chinese characters on a computer keyboard. It works, it is consistent, and it is now ubiquitous in China.
Well, it's not that simple though. You have 2x2 possibilities:
1. unaspirated unvoiced (av)
2. unaspirated voiced (aV)
3. aspirated unvoiced (Av)
4. aspirated voiced (AV).
German and I think English have 2/aV (b, d, g) and 3/Av (p, t, k), the diagonal so to speak (for the beginning of a syllable).
Mandarin has 1/av and 3/Av. So, 3/Av is pronounced the same - and Pinyin renders those as (p, t, k), as in German/English, so that's actually nice. Wade Giles renders them as (p', t', k'), indicating the aspiration.
German and English do not have 1/av (at the beginning of a syllable). Pinyin then chose to render them as (b, d, g), correctly indicating the unaspirated character, but tempting German/English etc. speakers to voice them (wrongly). Wade-Giles render them as (p, t, k), tempting German/English speakers to aspirate them (wrongly).
No easy solution. Plus, the apostrophes are so often ignored (e.g. Pinyin Taibei = Wade-Giles T'aipei).
Technically "p" in English does not default to the aspirated (pot) or unaspirated variety (hop). English speakers don't distinguish different word meanings when just those sounds by themselves are different, so they're considered homophones. Perhaps you knew that already and I just misread your comment, but thought it may be helpful info if not.
As an example, b in English is called an unaspirated voiced consonant, which means you vibrate your vocal folds, but send only a little breath when you sound it. You can compare it with p, its aspirated voiceless counterpart, for which you do not vibrate the vocal folds (voiceless), but sends a strong breath through your month (aspirated). Chinese does not have most voiced consonants present in English, so Pinyin naively uses b (also d and some others) to represent voiceless aspirated consonants, which does not sound like a b, but more like p in “spade”. This results in most of the foreigners learning Chinese with Pinyin bringing English pronunciation when they speak, and makes them sound way too stiff and thus awkward.
Wade-Giles, in comparison, is much more systematic, and does a much better job hinting speakers with European (especially Germanic language) background to sound more correctly. Bopomofo does not have this problem, as it basically invents a new set of scripts. Pinyin probably lets you pick up casual speaking Chinese most quickly, but beyond that, it’s a curse.
[Edit]: Voice “folds” not cords, sorry. Also fixed some typos.