When listening to reciters, I seem to hear virtually all of them applying the Arabic word stress / emphasis / accent rules listed below. Can they be applied because they are part of the Arabic language, although they are not part of the 'Ilmut-Tajweed or is it an innovation that is widespread, since expert reciters also seem to apply them? It is something subtle, but wrong word stress is clearly noticeable and sounds strange. Furthermore, not applying word stress seems to be very difficult without sounding monotonous.

Abbreviations:
C = consonant
V = short vowel
W = "long" vowel
S = short syllable: CV
L = long syllable: CW, CVC
O = overlong syllable: CWC, CVCC, CWCC

Notes:
1. Starting point is the pausal form.
2. Prefixes and the article do not affect the stress and do not count.
3. Suffixes do affect the stress and do count.
4. Mushaddad letters are separated, except at the end, before the pause.
5. The stress is on the bracketed ([.]) syllable of the word.

Arabic Word Stress Rules (left to right corresponds to begin to end):

[L]

[S] L

[L] L

[S] S L

S [L] L

[L] S L  (in Egypt: L [S] L)

L [L] L

[S] S S L  (in Egypt: S S [S] L)

S S [L] L

S [L] S L  (in Egypt: S L [S] L)

S L [L] L

L [S] S L

L S [L] L

L [L] S L  (in Egypt: L L [S] L)

L L [L] L

… [O]

We turned to experts in the field of tajweed and Arabic language for this answer, as we not familiar with the stresses referred to in the question, and have not heard these in the recitation of the Qur’an. The following is a summary of what we were told:

There are three kinds of accent in the Arabic language and therefore in Qur’an reading:

1. The hamzah. The Arabs used to refer to the hamzah as a “nabr” [meaning accent] and the Quraysh were known to eliminate hamzahs in their speech.  The word “nabr” was used then referring to hamzahs. They would say “Don’t make a nabr on my name”, meaning don’t say my name with a hamzah.

2. The raising and lowering of the volume of ones voice and changing the tone with no apparent reason, as done in singing. This is makrooh in Qur’an recitation [detested] as stated by Imam Malak bin Anas.

3. The accent which we have outlined on this site as done in certain states when reciting the Qur’an. This type of accent was outlined in old Arabic language books, most notably by Al-Mubarrid and Mekki Abu Taalib. Please see: http://www.abouttajweed.com/the-accent-in-recitation-of-the-glorious-qur-an/index.php  for the details on the accent in recitation.

As to what is heard and taught these days as to putting stress on certain syllables, such as we may hear from readers from specific geographical areas, this is more related to the local dialects than anything else and is not found in old sources. 

Insha’ Allah this sends some more light on the subject and answers your questions.

Wa iyyaakum. Wa assalaam alaikum wa rahmatullahi wa barakatuh.