First of all, ο τοίχος is masculine and το τείχος is neutrum. Concerning the meaning, τοίχος is a wall of a building whereas τείχος is the defensive wall built around a city with towers, bastions etc. Τείχος is also used in the plural with this meaning πχ σινικό τείχος=Great Wall of china, μακρά τείχη= Long walls of Athens
"see" when referring to vision is usually not used in the continuous tenses (is seeing, was seeing, will be seeing, etc.).
"my son sees Julie" = he perceives her with his eyes
"my son is seeing Julie" = he goes out with her regularly on dates
I imagine that your son is not in a relationship with the wall :)
I know about the ντ -> d and forvo. The problem was that this time the two letters were not part of the same word, but two different words. I will double down on this, since I don't get your justification and there's a possibility that we have a misunderstanding. Maybe is just my native language, but I don't see how "ton tiho" is easier to pronounce than "to diho" i.e., the full stop that you mention beeing required in the first case. So: what you mean is that the ντ -> d rule applies even if the ν and τ are part of different words? Thanks again for your patience.
I don't see how "ton tiho" is easier to pronounce than "to diho"
It is in fact easier for native Greek speakers, because the two words are pronounced so close together that the two consonants are linked and thus form the combination d. :) To separate them and enunciate exactly what is written would require the pause that jaye mentioned. The audio file is very good at showing the native pronunciation. So you have understood correctly, as confusing as the information might be. :)
The same happens with -ν before ξ- (ξ=κσ/ks), where you get the combination 'nks': δεν ξέρω sounds more like δε(νγκ)ζέρω- the(ng)zero! The (ng) is nasal and linked to a z-sounding s.
As much as we like saying that you read what you see in Greek, this is not true for imitating a native accent.
This is a language learning platform. That means we teach vocabulary and syntax in a variety of sentences so you get used to how the language worκs. We are not attempting to impart information of other kinds...not about what a son does, nor "I want bread".....nor any of the other ideas in the thousands of sentences.
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So, by learning the words and how to use them in phrases and sentences you'll be able to express, in time, your own ideas and understand what others are expressing.
And I should point out that it says..."My son..." not "the son..."/