Spanish nationality by origin

Biometric Spanish passportThe Spanish legislation regarding nationality establishes two types of nationality: "Spanish nationality by origin" (nacionalidad española de origen, in Spanish)—that is, a "natural-born Spaniard"—and the "Spanish nationality not by origin" (nacionalidad española no de origen in Spanish).

According to the 17th article of the Spanish Civil Code, Spaniards by origin are:[4]

those individuals born of a Spanish parent;
those individuals born in Spain of foreign parents if at least one of the parents was also born in Spain, with the exception of children of foreign diplomatic or consular officers accredited in Spain;
those individuals born in Spain of foreign parents if neither of them have a nationality, or if the legislation of either parent's home country does not grant the child any nationality; [i][/i]those individuals born in Spain of undetermined filiation; those individuals whose first known territory of residence is Spain, are considered born in Spain.
Foreigners under 18 years of age adopted by a Spanish national acquire, from the moment of adoption, the Spanish nationality by origin.[5] If the adoptee is 18 years or older, he or she can apply (lit. "opt for" the Spanish nationality by origin within two years after the adoption took place.[5]

All other individuals that acquire the Spanish nationality, other than by which is specified above, are "Spaniards not by origin".

Source: http://en.wikipedia.org/wiki/Spanish_citizenship

Please what does the above bold quotation mean?

This means that if you are born in spain and one or both of your parents is spanish or born in spain, then you are spanish by origin

If you are born to foreigners in spain who do not hold spanish nationality but are legal resident, then you are spanish provided your parents are not under diplomatic immunity at the time of your birth. If they have immunity at the time of your birth, what this means is that technically you were not born in spain

Finally if you are born in spain and you are stateless, then you are spanish by origin. Statelessness means at the time of your birth you cannot claim citizenship from any of your parents country of origin. For example, if you are born to chinese citizens in spain, china would not recognise you as their citizen as you were not born in china. Therefore you are are stateless. This used to be their custom but I understand it is now changed as chinese citizens can now pass on nationality to foreign born children

dancewith:

This means that if you are born in spain and one or both of your parents is spanish or born in spain, then you are spanish by origin

If you are born to foreigners in spain who do not hold spanish nationality but are legal resident, then you are spanish provided your parents are not under diplomatic immunity at the time of your birth. If they have immunity at the time of your birth, what this means is that technically you were not born in spain

Finally if you are born in spain and you are stateless, [b]then you are spanish by origin. Statelessness means at the time of your birth you cannot claim citizenship from any of your parents country of origin. For example, if you are born to chinese citizens in spain, china would not recognise you as their citizen as you were not born in china. Therefore you are are stateless. This used to be their custom but I understand it is now changed as chinese citizens can now pass on nationality to foreign born children

@ Dancehall

What if the parents are Nigerians? Can the child claim statelessness? Considering the porous state of Nigeria today, am sure most Nigerian parents will prefer their children to claim statelessness in this type of situation rather than claiming Nigeria. 

As a Nigerian your children cannot claim statelessness as they will be Nigerian citizen by descent wherever they are born. The difference is that china does not recognise citizen for those born outside china as they do not recognise dual citizenship. Now consider a chinese visitor in spain that now gives birth there as a tourist. since the father nor the mother has spanish nationality the child will not be spanish at birth. But then china also will not recognise the child as their citizen since it was not born in china! so the child becomes stateless and under the current rule, will become a natural born spanish